Also, the DANE support in Irssi was announced in September last year and I have only heard of one network where some of its servers have adopted to this technology. Even though there is only one client that currently supports DANE+DNSSEC verification, we still need the (big) networks to start preparing for the support of it, and help us reaching the point where we can secure our user connections even better :-)
Having SSL on IRC, even without DANE+DNSSEC, is still better than having no SSL at all.