Why are ranged using LB so much now?

[Sento-Frost]

SNIP.
Any other way of using it is inefficient.

I'd much rather save time in a fight for everyone than just indulge in the ranged's admiration of pretty flashy lights.

Well everyone's playing for his / her reasons, some like the "pretty flashy lights" and play for the show or might be in the mood for a show sometimes, others want it done the fastest possible.
But I feel the issue of people playing their class very very badly is of more importance for that matter than some people doing an AoE LB instead of just a bit more powerful single-target one.

If you don't like it you still have the option to go on missions with a full team of people you know who play for efficiency and won't waste a few thousands of damage for something they like.