I’m pessimistic that this will actually change much, or drive users to Mastodon. Just like, as much as I’ve been loving my time with Kbin/Lemmy, I don’t think people are ever going to leave Reddit. Most people appear to have a way, WAY higher bullshit tolerance than I do. It’s sad. The old guard are unusable, and the new options are withering on the vine.
There are accessibility concerns with doing that, if the poster doesn’t provide alt-text. Images are basically unreadable to the vision impaired.