

It’s used in the context of a micro-blogging platform where your feed consists of individual posts that don’t show the whole comment thread. If I replied to a post on mastodon, my followers only see my post on their timeline unless they click on my post to see it’s context. A quote post can be used to present someone else’s post to your followers, with whatever you want to say about it.
Honestly, I mostly just play a lot of old games that still support consoles, cheat codes, or mods.