I've played a bit of most of every character, and it's nice to have a character that has strong mobbing potential over other characters for once. Mages are good, Xbowmen are good, heck even 5th job bowmasters are good at mobbing. However most updates these days have turned most of every class into a bossing character that hits single targets 200 times a second, and most bosses released these days have a gigantic paywall included with them. I mean you fight a boss, get it's equipment, find out you need to spend 6$ to trade that equipment to profit from it, and if you don't want to buy nx you're out of luck.

Having characters with high level mobbing capabilities like jett or even pre-BB mages help with developing not only those characters faster, but it allows to develop other characters faster by straying away from boss related content which is diminished with time (and power creeps). It helps normal players farm items like Nodestones faster, it helps people gain mesos normally, and it gives people incentive to play content that isn't boss content related.

Honestly nexon, please don't nerf Jett, I haven't enjoyed playing a character like this since I started my Bowman.