Could be, though it's a little clunky to use it that way still. You can subscribe to Lemmy communities from mastodon but you will see every comment as a 'toot' and it's a bit of a clusterfuck to view larger subs that way. It can be great for smaller ones though. I have seen people post and comment here from mastodon but that platform seems like it is built more for following individual accounts and hashtags. Kbin has more capability in the microblogging dept. if that's what you're looking for.