Sure, I was thinking about authentication for certificate issuance purposes (where Let's Encrypt already enforces DNSSEC validation for all issuance-related DNS lookups where DNSSEC is present on a zone—in fact, invalid DNSSEC signatures aren't an uncommon reason for issuance problems).

But DANE enforced by clients would also be quite valuable for preventing problems due to CA misissuance, or for the problem recently highlighted by security researchers that someone might deliberately allow a domain to expire while still possessing long-lived certificates for names under that domain.