Earlier quoted context omitted.
I'm running a file server with a pi and a USB enclosure for a huge sata drive, and it works fine. Could be neater though.
Yeah, I like data integrity and failsafe setups, so your solution feels to me like standing on 3 stacked chairs while fixing something with live wire.
It gets better, I'm powering the pi through its own powered USB hub. I was afraid doing so would short something but it's held up so far.