This lapras worth something to power up?
not trying to brag about it but i hatched all of my 5 laprases from egg. but this one is 95% iv. i have like 75 candy and i can throw 1 lapras (crappy iv only 73 wg/b, for me not worth to keep or prestige.) just for the sake of the candy. so if i power up this one it'll be somewhere 2316 cp.
will it good to hold up gym where everything is either, tyranitar, snor, dn, rhydon, vapo or blissey. it has a good hp tho. 200 something.

Answers
Dragon Pulse is only single super effective and you don't get STAB bonus. Comparatively, ice moves do 1.56x more damage against Dragonites compared to dragon type moves, which explains the noticable damage difference.
Lapras' problem is it's low max CP keeps it at the bottom of a gym. Good dueling ability doesn't mean much when it only gets into one battle before being kicked out. But if you care more about how it actually performs in battles, then it does perform really well, even with a suboptimal moveset.