I guess i could use a USB3.0 but from my understanding the throughput and io was better on thunderbolt compaired to USB 3.0.. I'm going to be using it for hd 1080p stuff and maybe "MAYBE" a 4k video..
An SSD on TB vs. USB3 is very close in speed. See tests below. The big advantage of TB is it supports TRIM where USB does not.
http://www.barefeats.com/hard168.html
http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html