This is A theory I came up with for a dissusion of the Steven Universe wiki.
This is an edited version based of feedback I received from the disscusion. Which you can read here
Many people say Pearl shouldn't have a weapon because she is a servant and that she had to learn how to summon one. This theory doesn't make much sense to me because is doesn't explain why Homeworld would give her the potential to summon a weapon in the first place.
Here are some other points I would like to make
It's not just soldiers that have weapons
Civilians can have weapons for self-defence even if there not ment to fight.
How do civilians defend themselves
Gems are a race that colonize other planets meaning they will face many dangers such as wild animals or hostile natives, so they all need to be able to defend themselves.
My guess is that when designing Gems, Homeworld decides what powers they need to do there jobs then worry about self-defence.
Some civilian Gems don't need weapons as there powers can double as such (eg Bismuth has shapshifting hand for constrution and Lapis Lazulis water control for terraforming can both be use to fignt off threats.)
- Note about Peridot:
- In Too Short to Ride it was revealed that Peridot was made (presumably) made without powers due to a supply shortage and had her limb enhancers to make up for it. These limb enhances came with tools and abilities to do her job as a technician but also come with a built in blaster.
- (she discovers metal powers in the same episode but that's a different theory)
What about Pearl
Pearls powers include duplication (possibly for multitasking), holographic projection (for playing back important information to her mistress, and/or for entertainment) and telekinetic power over sand and clouds (purpose unknown)
Non of these powers are effective against an apposing threat so pearls are given weapons in case of danger.
But why did our Pearl need to train?
well it's implied that our Pearl may have belonged to a Diamond and as such never needed to use a weapon (prior to rebelling) due to the mistress already having Quartz guards and over defences.
So it's not a question of "learning" but rather "rediscovering" her Gem weapon.
Civilian Gems are given ways to defend themselves against threats whether it's with there powers or with given weapons.
Our Pearl likely belonged to a Diamond and never needed to use her weapon and forgot how to. She then trained her self to summon her weapon sometime after the Rebellion.