Any need for UHS-II SD cards in X-Pro2 if not lots of burst-mode?

My older non-UHS-II cards have been working fine in the X-Pro2.

Am curious if there are any real benefits or noticeable performance increase if I switch to a UHS-II card.

I don't do burst mode much. And I understand that the X-Pro2 has a large buffer [does it?]

So maybe my older cards will work fine if I don't mind waiting a bit until the camera finishes writing out the contents of the buffer to the card?
Are there no other performance issues from using slower cards?

I'm asking as an...

Any need for UHS-II SD cards in X-Pro2 if not lots of burst-mode?