Due to my skepticism I never use any QR code when it comes to exchanges or wallet, it's better to copy-paste the address and triple check it.
some people like to 'air gap' their exchange deposit away from their actual cold store.
that way they are not using the same screen/system as they are when logging into websites.
EG phone app for own personal stash and normal pc to log into services
thus copying/pasting is not possible, and writing out address is inconvenient especially if you make a spelling mistake, you can end up sending funds elsewhere
the main thing is dont just scan a QR code and send funds to it instantly., instead check what you scan matches the address of the service you want to deposit to.
also dont just look at the first 8 characters
for instance bc1q is pretty much always going to be in segwit addresses and then its pretty easy for someone to 'vanity gen' many addresses that contain the same next 4 characters
so look at the whole address and make sure they look the same (usually better to start at the right side of the address rather then the left side) when comparing
