Your set bonuses/level shifts/temp powers aren't restored instantly when you rez (even auto powers have an activation interval and duration, so when they're disabled due to defeat, they can take 0.5-10s to turn back on), which means Renewal of Light only has base hit chance (75%) and comparatively unimpressive damage (even with all three pulses, it won't defeat minions). Plus, it slows enemies, so they're actually forced to stay near you instead of giving you some breathing room if they aren't knocked away (that boss or EB with massive KB resist isn't really what you want to be still teabagging you after you rez).
Return to Battle's inspiration dump is more tactically sound and immediately useful. Those inspirations make it a lot easier and faster to clean up the spawn and let you get your feet back under you. You're protected from a lot of incoming damage after the Untouchable effect expires, and you're hitting harder and less likely to miss. Return to Battle means you don't have to run away or worry about being put back down, you can just get back up and kick ass like nothing happened.
Testing. Different characters, but since everything's zeroed out on defeat and not reactivated immediately, essentially a level test platform.
If set bonuses, temporary powers and other effects which persist even when you're defeated were immediately applied to Renewal of Light, it'd be a better rez. Removing the Slow would also bring it closer to parity.