It seems like gems value physical size and strength rather than the unique powers certain types of gems are granted. Remember strawberry field? It was littered with melee weapons.

Gems are functionally immortal, so what's the fun of drowning your opponent if they don't need air, or setting them on fire if they are relatively fireproof, or freezing them if they are strong enough to break out of it easily? That, and the way Homeworld used fusion in "The Answer" shows that they really did only use fusion to make "weak gems" stronger.

I feel like they are setting that up to be a plot point. We may learn eventually that Rose and her army only held Homeworld off because they used these special powers, instead of relying on brute strength. In "The Answer" (again, I know) Rose took out Ruby^3 with an unseen technique that split them apart instead of poofing them, rather than attacking with a sword.

So, I think that the specific powers the gems have (like lapis's hydrokinesis, Garnet's lighting, and Steven's healing/plant powers) will become very important later in the show.

Also, remember that one time Pearl manipulated sand? I wonder if they will do something with that later on.

Duh, that's the point: if Lapis, who was shown to be so powerful, is afraid, then what Homeworld can put against them is even worse. I mean, someone did manage to crack her gemstone in the past. Besides, her powers are only good on an Earth-like planet – if they are taken to Homeworld where there may not be any water, she'll powerless against other Gems there.