Given that Barrier Core Epiphany only gives insane defense for the first 30 seconds, then 7.5% defense for the next 30 seconds, and 5% defense for the last 60, I'm thinking there were either more incarnates around than just a couple or someone was bubbling. And none of them were running Ageless?
Destiny already comes with a heavy decay rate, and you need certain T4s to make it perma. Its fine as it is: An 'oh shi-' button and/or way to shore up build weaknesses. Nobody takes it for team considerations aside from incan.