[pja]

I ask because one solar mass worth of energy sounds like ... a lot. At least to me as an astronomical layperson.

It’s a ridiculously large amount of energy. Someone might want to check my numbers, but a standard candle Type 1A supernova releases ~2x10^44 Joules. 1 Solar mass energy is equivalent to roughly ~2x10^47 Joules. So this black hole merger is about 1000x times the energy released by an ordinary supernova. And there’s nothing ordinary about a supernova, pace https://what-if.xkcd.com/73/