It's a different build-out to a data centre that can host video/YouTube content (fast CPU, no GPU, large number/size of hard drives), or that can run web servers (fast CPUs, low to average hard drive capacity).
No you're absolutely right. The only difference that I can tell is power requirements are legitimately higher because GPUs consume more electricity. More cooling is also needed because there's more heat generated. Aside from those two things, it's a plain old datacenter that companies have been building at break neck speeds since like 1996. Now that I think about it, how come there's no panic about additional Internet backbone capacity needed to support these "AI datacenters"?