I know this hasn't been posted in for over a month, but I want to add, it's not just gamers. Sometimes, we like using a desktop.
You can do more with a desktop, like add addon cards more USB port, etc.
I have a desktop connected to my TV for my entertainment system, so I can watch my downloaded movies, shows, watch Youtube, etc.
I mostly use a desktop beccuase of preference. Sometimes, I use a laptop, like if I'm in bed.
PCs are generally easier to use than an mobile phone, or tablet; becuase apps are limited, for one thing.