I don't see the point of keeping a genuine MS-DOS PC (with Soundblaster 16, Roland SCC-1, Roland CM-32L) around anymore because MS-DOS games tend to run just fine on DOSBox, with pretty much perfect support for all those sound devices with VirtualMIDISynth, Munt etc. It is even easier than with a real MS-DOS machine because you can effortlessly make separate "config.sys/autoexec.bat" even for every game if needed, and also you can change your "machine speed" easily with DOSBox, as some MS-DOS games were designed for certain CPU speeds (e.g. even in the GOG version of Shattered Steel, the laser weapons don't work right if the CPU is too fast, but with DOSBox, you can easily change the "CPU speed" even during the gameplay).
For old Windows games that might have issues on newer Windows or newer PCs, I still have several older PCs running either Windows XP and/or Windows98SE (albeit I very rarely, if ever, run something that works in 98SE but not on XP... I did that with the Direct3D version of Dungeon Keeper though, IIRC).
The main reasons to use the older retrogaming PCs are:
1. It is a retail CD/DVD game with copy protection that does not work on Windows 7, let alone Windows 10. I guess finding a suitable noCD crack fixes most of these, in case you are still able to find such working cracks, especially for an updated version of the game, not just the original 0-day 1.0.0 warez version.
2. The game is designed for a certain CPU speed, e.g. Interstate'97 (even the GOG version) and Mechwarrior 3 physics break down if the CPU/framerate is too fast. So you need a slower PC for those.
There used to be also that some 3D games relied on certain features of older 3D cards (e.g. I recall Heavy Gear 2 graphics being broken on modern graphics cards because the differences in how Z-buffer is handled in old and new graphics cards; also I think some Splinter Cell games relied on certain NVidia Geforce features for lightning etc. that don't work similarly on newer graphics cards), but I at least hope wrappers like dgVoodoo2 can fix these kinds of issues nowadays. At least it is able to fix e.g. Might&Magic 9 graphics issues like not seeing anything underwater...
Some say they like to play on an old PC with CRT etc. because then the game feels more authentic, but I couldn't care less about that. As long as the game runs fine, I'm fine, even if I am playing it on a Windows 10 laptop. The same goes to playing old console games on an emulator, vs. the original console connected to an old CRT TV... I just don't care, emulators are usually fine and even preferred, due to offering save states support etc.
ConanTheBald: I have i486 with Windows 95 and DOS on it. Only way to install games on it is via 3,5" floppy drive. Which means trouble.
Why do you need to use a floppy drive anyway? As far as I can tell, old floppy MS-DOS games didn't usually have any copy protections, and they were used to only install the game, not running directly the game from the floppies.
For instance, I originally installed Red Baron and Wing Commander 1/2 + expansion packs from the original floppy disks, back in the 90s.
However, after that initital installation, I never had to touch those installation floppy disks anymore. I could just zip (or "arj") those installation directories myself, move them to another PC, and continue playing there.
To this day, I still have those original installations for those three games, running nowadays happily in DOSBox. I even have the save games there intact, all the way from the 90s when I played the games. The original installation floppy disks... I think I threw them to trashbin already back in the 90s.
So, floppy disks? For what? I am pretty sure that if you can buy some old MS-DOS games on floppies, the magnetic data from those floppy disks has perished already decades ago, and the floppies are useless.