There's nothing super-special about the host. The accelerators are the special part (and, as described elsewhere, they are orders of magnitude more powerful than the Edge TPU). However, if you're an academic/independent researcher, being able to access a system with that much system memory/CPU cores for free through TPU Research Cloud is potentially appealing even without the accelerators.
I know just enough about the architecture to facilitate using TPUs for research training runs but I'm not sure what's so special about the host?
Sure it's beefy but there are much beefier servers readily available.