I believe it had to do with the change from the old addon format to the new one in Firefox.

Bitwarden doesn't seem to have any problem copying passwords using a new-style extension with no binary install.

I recall that the initial release of the Web Extension support was a bit threadbare, and/or that they had to change the extension ID or something of that sort, but it's also possible it was left out for existing design reasons/as a cudgel. In either case this whole thread has been useful for alerting me that I should re-evaluate if Lastpass is the optimal solution for me.

I switched to LastPass from 1Password because I hated their whole mobile sync thing where you had to be on the same wifi and start your Mac app to sync etc. I understand that it's more secure that way, but that trade-off was not worth for me. Has that changed in the meantime?

Thanks