Shining Light  

This spell has its own uses. We have many spell gems. I have this and BoM memmed always. You aren't going to always want to use BoM because it costs twice as much mana, and it blacks out your spell gems for a second or so. This is one second (That isn't a long time. Not as quick as BoM, but It's not like it is our 4 second heal) , and you can follow it up with BoM or your HoT spell line right after without having your spell gems blacked out.

Maybe you just don't need that much of a heal, or don't want to use an unnecessary amount of mana. It is what it is. A good SMALL heal. = )