Well, really, not everything in life has to have a pragmatic and useful end. There are people who collect the weirdest things, really. If you stick to things that only have a 'useful end', that's not too healthy! Why do people drink beer and watch sports? That doesn't produce anything 'useful' either. The reason? People need to fool around and recreate to stay sane.
Lasers are about a "2" on a scale of 1-10 as far as weird collections go.
To me, lasers are like nerd eye candy. People collect art, guns, cars, beanie babies, sports cards... why not lasers?
I also collect odd LEDs. I have some of the strangest wavelengths anyone's never seen.
Hobbies and collectors have existed since human civilization began - humans like to do things recreationally, and they like to collect. It's perfectly normal.
Some of the other expensive hobbies I have include audio (I collect rare vacuum tubes), and photography (I have a big collection of impressive lenses for my DSLRs.) ... Lasers fit in perfectly with this!
Pretty simple - it's entertaining. And really, that's enough justification for it. Anything that gives you enjoyment in life... Shooting a beam to the mountain across from me makes me laugh and smile.
And after a hard day of work, that's worth it. Even if there's no "point" to it.