[opan]

The max speed isn't as important as much as the fact it can go past the USB 2 limit in speed.

[coldtea]

For determining whether it's USB 2 or not maybe (and even then it might not be so clear cut).

For actual use the actual practical max speed is far more important. It would be useless if you wanted something better than USB 2.0 and it only did 1.1 times the USB 2 limit for example.