*Don't ever buy a Micro, or Mini ITX case, those boards are severely limited in USB's and expansion options.* *Always get a full size board and case, if you have any plans on upgrading your performance or storage capability.* *Also, the tiny cases are difficult to work with, are too narrow for most cpu coolers, and they won't fit a large graphics card.*
Ummm... Maybe.. a few years ago? But these cases have evolved (like everything does) and they can house even 4090 video cards these days. Yes, you'll have more flexibility in your build with a ATX case, but for some people, maybe they move their computer around alot, or physically dont have the room for a larger case on their desk... In these kinds of situations, they might have no choice but to go to a SFF (small form factor) case. Its personal preference.