I don't specifically store candles for emergency use, but my wife uses tea candles so we have lots of those at home. She buys them by the bag full and they are cheap.

I think I would only use candles for a simple power outage. The main disaster for my locale is either an earthquake or wildfires and in both cases, having an open flame around is not the best option, even using a decent candle lantern to contain spills and such. I would much prefer sticking to battery powered lighting in such situations.

That said, there is certainly a calming effect to watching the flickering, warm glow of a candle in the dark night. Much more interesting than staring into an LED camping lantern!