Skills, Skill Mats and Power ...

Stenun

If I have a character who has a Leader skill but I have no intention of ever using them in the Leader slot, is there any point increasing their Leader skill?
I get that it will increase their Power and therefore might make people more hesitant to attack me (e.g. in Arena or Territory War, etc.), but other than that will it increase their stats? Will it make them a more powerful character to use? I don't see any indication that it will so I have always been careful about which Leader skills I spend resources on, especially Zetas, but recently I have encountered some versions of Bastila Shan who seem even more deadly than my version despite my having her at maximum gear, all MK-VI E mods, and all skills matched other than her Leader skill.
It could just be the case that the opposing Bastila's have had even better Mods than my ones - even better stats than the ones given by my Mk VI E mods - but I thought I might as well double check about her Leader skill too, just to be sure.
And of course depending on the answer, it might affect a whole load of the rest of my characters, too!

Vendi1983

I only really bother with unused leader skills on pilots, as any upgrade increases the stats on the ship. Outside of that I usually stop upgrading them once they need purple mats.

Kookermader

If they are a ship crew member, then upgrading their skills will increase the stats of their ship. If they are not a crew member, then upgrading their skills has no other effect than the one in the ability description, so no additional stat boost. If you are never going to use a certain character in the leader slot then their leader ability zeta will have no effect, unless they are also a pilot.

leef

Upgrading a leader if you're not going to use the character in the leader slot is totally useless.
pilots are an exception, every upgraded ability improves the stats of their ship.

Stenun

OK, so the only possible explanation left is that my opponents have had better luck with the Mods they've found than I have. Not much I can do other than keep hunting for more Mods but at least I now know for absolute certain!

Thanks for all the answers!