I appreciate the tip but I guess that is useless for Flixbus. Flixbus says they only accept credit card, paypal, google pay or apple pay… Nothing I would go near.

Indeed usb3 is very useful for disk i/o. I wouldn’t treat it as a deal breaker though. USB 2.0 is good enough for OS installations, especially if you do a Debian netinst which uses minimal disc input (although USB 2 is perhaps still faster than your WAN uplink). For backups, it depends on the volume you are dealing with. USB 2 is good enough for small data and incrementals but if you have to transfer 500+ GB then you would want one of:

• eSATA
• NAS storage (over ethernet), or
• USB 3

All of those buses can be added to a pre-USB 3 machine. But if it’s a laptop, the usb 3 expresscards may be hard to find locally because they never really got popular.

What do you need usb3 for? In most use cases, USB 3 can be added. I have a usb3 expresscard in my laptop, which has an external power input from a USB port to drive things like USB3 external hard drives that rely on the USB bus for power.