This is pretty short-sighted, considering that there are mobile devices out there that do not have an official Reddit client, such as all the various Linux phones.
They're on a dark path, when I signed in using a different device (on the same home network) it triggered a total block on my account that required adding an email address.
What's a good alternative though? I tried Lemmy a while back and whilst FLOSS communities there were pretty active, others not so much.
Only reason I use Reddit these days is for r/sysadmin and r/SCCM, lots of useful content there that saved my bacon on multiple ocassions - especially on Patch Tuesdays. Haven't seen this sort of active userbase and content posted anywhere else.