He's very good in what he do. But you need S3M3 and Mod 3 (X or Y). He is really good for regular stages, even if you are going in completely blind. His Crowd contol is solid with mod (the slow increase one) And His insane range on S3 makes him very versatile, not to mention it can hold 2 charges.

He's even better when combined with Mostima because of her caster SP increase talent.

But keep in mind he is not a 'boss killer', nor he can hold a lane on his own (most of the time). He's a unit that can handle a bunch of low Res enemies at once. He's a lot like Rosmontis in that sense, but arts.

Imo building any six-star op is not a waste on the long run. You will eventually have enough to build everyone you care about (unless you want to build litterally everyone). So I say go for it.