system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Does a Patronus Charm serve any purpose besides anti-Dementor duty? What else can it do?
gpt
It can provide endless amounts of personality quizzes on the internet

On a serious note, there are a couple of other uses that have shown in *Harry Potter* media. Kingsley Shacklebolt once used his as a messaging device, sending it to the dancefloor at Bill and Fleur's wedding: when it opened its mouth, it spoke in his voice. McGonagall did the same at one point, and was proficient enough with the charm to cast three at once.

Snape also used his Patronus to guide for Harry through the Forbidden Forest without revealing himself, which would be another niche use. You could also use it as a light source in dark places if *Lumos* wasn't good enough for you.

Since Death Eaters are apparently incapable of summoning Patronuses, you could also use it as a test to prove someone was or wasn't one, if you needed to do so. Same deal with proving someone's a werewolf or not, which is why Lupin tried to never cast his. However, since Patronuses are literally the most difficult defensive spell to cast, whoever you were trying to out would have some wiggle room.

Finally, since you can only summon a Patronus by thinking about the things that make you happy, what you hope for in life and the people you love, maybe wizards could use their summoning as a form of self-care?