> First, TLS outages pop a warning box up on your screen, and DNSSEC outages make your site entirely disappear from the Internet. So that's a difference.

Meh. If you handle your site correctly, you have at least HSTS, in which case, TLS errors are also game-over. If you don't have HSTS, well I have bad news for you.

The other point stands though (risks are higher and rewards lower for DNSSEC).