Experience After 80
You just get a skill point.
You continue receiving skill points after each “level up” after 80. Those skill points can be used on many items needed in Mystic Forge recipes for unique gear.
and well both my thief and my mesmer evne ahd a few skills to unlock after lvl 80 still. and as other said yeah certain high tier recipes require mats bought from skill point, legendary weapons being one of them but not the only one, requireing no less than 200 skill points