I’ve usually used a big case so that I don’t need to worry about practical things like this.
Building a computer in a tiny case would be an interesting challenge, but it wouldn’t be very practical or fun in the long term. Designing and building could be fun, but once it’s time to upgrade anything, it’s also the time to sell the whole box and let someone else deal with it.
From what I see or just my personal preference, itx cases seems to be more focused on asthetics than functionality. I do like the looks of it and would like to switch to some open itx builds at some point but idk if it's worth it with all the drawbacks.
Depends what you consider its function. A small case is much more convenient for some people than a hulking mass of steel.
I remember when giant Antec towers were popular. Now people only have NVME drives instead of 3.5" disks, and most modern PCs don't even have optical drives anymore. The biggest thing nowadays is these enormous GPU coolers.