In PBB you can use both methods like:
https://pbboard.info/forums/u1526.html
https://pbboard.info/forums/darq5.html

Why you care about members page to be like this?; it is not very important to archive.

PBB use numbers style in html links, sorry we can't change it.
This method also in many forum prpgrams.

For example in MyBB it is like:

user-111.html

You made a topic about html short urls, we don't have anything new to add.