Troops vs Fighters

[Sardia]

Under what situation would I want to use troops over fighters? (Balance Mod, 1.11)

I've a big fan of conquering planets via dropping forces onto planets and fighting it out on the ground. However, I've noticed that fighters are superior to troops in a lot of ways. They can travel between planets and they can be used for either fighting past the defenses or invading the planet.

[Captain Kwok]

Troops are the only units that can improve planet happiness - which is particularly useful after conquering an enemy planet. They also can't be targeted by Point-Defense from Weapon Platforms.

[Sardia]

Oh, I guess I should leave 1 troop on each planet for good measure.

Can you explain to me how carriers and fighters store their ordnance? Fighters were built with a certain amount of ordnance built into the fighter, and it would resupply from the resupply depot and other ordnance stores. Right?

Do fighters resupply every time you launch them? Do they lose the supplies that they take when you recover them?