answer a couple of questions?

[Khalus]

Crystals are used with the 8 "of the Hand" classes for synthesis {or crafting} If you don't plan to ever play these classes then just list them for sale on your character's Bazaar, your retainer, or find other players offering to purchase them and sell to them directly.

The elemental points from what I've come to understand effect only the harvest rate of crystals from their respective demographics while playing the 3 "of the Land" classes. Crystals are more frequent based on where you are in the world or from certain rank/types of nods, but with points in the elements you can increase the acquire rate, though I personally have never seen a huge difference, so I just raised them evenly.

No, the elemental points at this time have no effect on fire or ice damage. {doubtful they ever will}


Its really up to you if you want to craft or not, if its something you enjoy, but in honesty and as you just said, everything you could ever want is already available from other crafters, and gil is very easy to get. Its a just a matter of finding each piece you want, then saving up the gil if its really expensive and not cheaper on another retainer. Just takes a bit of time...