weapon skins
It has always been about looks/skins. Everything is a build up to a skin you want. Karma comes easy if you at minimum finish dailys for jugs of karma, do events in Orr (Straits of Devestation, Malchor’s Leap, and Cursed Shore) and Frostgorge Sound with a guild/group. Also WvW is a great option too to tag events & keep on trucking around, even with a zerg for easy karma mode.
http://dulfy.net/category/gw2/fashion-gw2/
You can use this link that has a verity of weapon skins & shows how you can get them. Some weapon skins can be found per zone so u dont have to buy a high priced item off the TP, it all depends on what look your going for.
Some weapons dont have the stat combo certain players arent looking for but they like the skin, so thats another reason y people will buy a weapon just for skin. Just depends on how you build your character.
The exotic to exotic comment is a lil confusing, since i could take a dungeon skin & put it on a white starter weapon on an alt & use the low lvl stats while keeping the high lvl look. Same goes in reverse, you could take a starter weapon & put dungeon stats on it for your high lvl character. – All of it depends on what look you want & stat combo.
Good luck on finding the look you want, if you need help on what style/look, feel free to ask. 
EDIT – Changed link to direct to weapons
(edited by Hebee.8460)