I game regularly on a Non-Gaming laptop.
I've had numerous gaming laptops and generally none of them lasted more than two years, but this was also 10+ years ago now and they seem to have gotten better. For instance, a friend of mine gave me one from 2016 and my kids still use it daily to play games on.
That said, here are the Cons:
1. Heat - It's going to get very hot, so what's your plan? If I'm playing something intensive, I have a tray with a cushion on the bottom to set my machine on. This has the added benefit of allowing me to use a mouse, if necessary.
2. Noise - Are you bothered by fan noise? There will be a lot of fan noise. This generally doesn't bother me, but I know there are plenty of people for whom fan noise is their bane.
3. Inferior everything - Your monitor, speakers and performance will be worse than your desktop. Can you live with that? My Gaming PC has a nice looking 165Hz 1080p monitor. My laptop has a 60hz, pretty good 2160x1350 (weird, eh?) monitor. My Gaming PC has mid-range Logitech speakers with a subwoofer for pretty excellent and loud sound. My laptop has two downward firing speakers on either side that sound pretty good...for a laptop. My Gaming PC can run anything I throw at it with High settings at 165hz, no problem. My laptop won't run even fairly simple looking modern games (Frostpunk is right out) on its integrated graphics. It'll run things better with my eGPU connected, but that is a large desktop sized box on the floor by the side of my couch. Still, it doesn't compare to my desktop. And even with an eGPU there are compromises.
Going along with that, because that paragraph is already a behemoth: Worse keyboard (though I love my Thinkpad keyboards) and a relatively cheap SteelSeries Bluetooth mouse. Versus my Gaming PC with an expensive (to me) Keychron mechanical keyboard and a decent Logitech wired mouse with lots of software adjustments.
4. Lack of modularity - sure you can upgrade some things on your laptop. I've upgraded my thermal paste and my SSD and on older machines, the Wifi card and RAM, but many laptops these days are soldered almost all the way through, so you won't even be touching the RAM. You're going to want to get as much as you can for what your budget will allow.
5. Expense - My 13" Thinkpad X1 Nano cost me about $600 last year and then I've spent another $400 on my eGPU setup. I won't include the SSD, as that cost can be shared with a desktop setup. So I'm in $1000 on my laptop in a year. By contrast, I've had my desktop in its (mostly) current form since about 2018/9. In 2023 I upgraded the CPU to a Ryzen 5600X ($150 or so at the time), added 32Gb of RAM (Think that was about $60) and went from a 970 GTX to a 6700XT ($320). I also bought the new keyboard and a new monitor (Somewhere around $250) for a total of around $780, so about 3/4 of the price of my significantly worse laptop.
Now, all of that said: I do 90% of my gaming on my mobile devices (I'm including both Laptop and Steam Deck in here), because there is no replacement for being able to game how I want to. No longer am I tied to my desk in my office, now I can sit on my couch with my wife in the evenings, stretch out and get some game time in. I can take my laptop into different rooms or travel with it and play whatever I like (eGPU setup not withstanding. I usually just stick with whatever my integrated graphics will run when travelling). If I were to describe gaming on a laptop and why I choose to do it over my Desktop in one word:
Versatility
Versatility is probably the only Pro to gaming on a laptop, but to my mind, it's an enormous one. I'm willing to sacrifice a helluva lot just to be able to game when and where I choose versus being chained to a desk with limited options for comfort.
Now the next stuff I will say comes with a caveat:
I do not buy Gaming Laptops anymore. I prefer the build quality, comforts and control methods that Thinkpads offer over any performance gains a dedicated gaming laptop can give me. Again this comes down to versatility for me.
At any rate, if I were going to buy a gaming laptop in 2025 I would look at previous years models. I don't think I could ever justify spending $1000-$2000 on a brand new machine. Sure you'll get the latest and greatest, but that's a lot of money to spend on something that is going to be outdated and show performance diffiencies relatively quickly. I would much rather have someone else that the depreciation hit and buy something used with a little less performance and then I won't feel so bad spending another $500ish in the next two or three years to get something better.
You can find some pretty solid deals on Refurbished laptops on Ebay:
Such as here
And Here
Now, that said: being a cheap bastard and loving used electronics, I've had bad luck with Refurbished stuff in general. Refurbished to me generally means it was beat to hell and minimum expense was used to get it back into usable condition. I tend to find that "Used" is better, as generally people selling used have been pretty mindful and careful of their items and tend to take care of them much better, so you'll receive them in much better condition.
See here as an example
At any rate, I think
@ZedClampet offered good advice from a different point of view, so consider your options. Again, I'm a cheap bastard and I only buy used Thinkpads, plus I love a project, plus I love to repair, fix or upgrade things in anyway I can, so you may want to take my buying advice with a grain of salt. That said, gaming on laptops is a great compromise and while I still do occasionally use my Desktop, most of the time I would rather just not play a game that doesn't run well on my laptop than be chained to my desk for it.