https://www.usr.com/education/usb3-peripherals/
USB 2 versus USB 3 data transfer speed is huge.
I have two BDP-2s and a BDP-1. None of which has an internal drive. I have a couple of my external SSDs on USB 3 cables, but I don’t think it makes a bit of difference with respect to music transfer. The USB 2 spinning drives access the music the same as the SSDs using USB 3.