I have installed this on a couple of sites, and it seems to be working fine. I can see the different style of password hashes in the database, and logins, etc to continue to work as before. So all good.

I am wondering, though, why the pull request here hasn't been warmly received. To a non-coder like me, it seems a good idea to build in some future-proofing, and the proposer argues that it has no downside. Is that right?