Depends on what you're building. If you're looking for an overpowered SFF type of platform then yeah those AI Max+ builds may be what you want. Just keep in mind a lot of those are integrated motherboards (non-upgradable parts) and usually have minimal storage options and slots for add-in cards.

The other reason those AI Max+ PCs get a lot of press is that there's still not a whole ton of CPUs with capable NPU built-in aka Windows Copilot+ compatible. AI Max+ happens to be one of those. (whether NPU is actually useful right now beyond Copilot+ is a whole other discussion)

So if you actually want a more extensible build out and don't care about this Copilot+ stuff then traditional builds / non SFF builds are probably still more in line with what you want.