Could be small or big.
My answer has always been that, Linux can't handle everything I'd ask out of it that I normally can with Windows. I know the games issue has been progressing far from the days when that used to have been an archaic flaw with Linux for the longest time. Games might not be the issue except for some concerns I have for some games.
I was taking some time a few moments ago, to check if a program called Firestorm Viewer would work on Linux Mint which could've been my distro of choice. And the description written on the linux page described exactly the kind of concerns I'd have for compatibility and usability from going Windows to Linux.
They said that their viewer was tested and designed to function mostly with Ubuntu and while it could work with other distros, it's not to be expected to be smooth.
That's the kind of sentiment and concern I have always had with Linux if I were to go from Windows to it. There are programs and tools on Windows that I have that are used for specific purposes and I know they will not function on Linux. Furthermore, incase anything breaks down, any and all solutions would only be applicable to that thing that would be far easier to solve than just being SOL if I was on Linux.
It is something as a user that I just can't simply afford to deal with on a regular basis if I made the switch.
So while I may not have too much of an issue running games, I won't have too much of an issue using alternatives, I won't have to deal with the Windows ecosystem .etc I will just be running into other walls that would simply make me second guess my decision and make me regret switching to the point where I would dip back into Windows in a hurry.
That's exactly how I feel about it as well and largely contributes to my hesitation.
I read and hear how so many people just gush and gush about how Linux Mint or this distro just 'works out of the box'. What they don't tell you, is how they must have had to spend hours getting something to work. Like sure, Linux Mint or a more friendlier distro will work out of the box - if you do nothing but just browse online and maybe install/uninstall programs you may want or need from the software package manager.
But I have had my battles before trying to make things work on linux distros, like getting proprietary functions of a browser to work. Hell, I have even had to fight a little just to get a displaying clock! Like with its formatting from 24hr to 12hr, I'm not saying getting it to display or anything but I don't get this desire to default to a 24hr format. And I have had to fight at times to switch formats.
The point is, I or others should not have to spend more time than we need to, to get things to work when there is already an OS that readily does that without question. It doesn't make us dumb, it doesn't make us incurious or boring or uninterested in computers and technology. It's about patience and respect of time and if some Linux distro is not going to respect my time or patience, regardless of how welcoming it appears, then it is not worth swapping to.