Thats nasty. Taking a cut from donations/tips.

all the content creator has to do if he wants a bitcoin tip is to put a bitcoin address in his video information. sure, vimeo could take steps to make this easy and prominent for its users with direct bitcoin support, but its not really necessary as bitcoin makes this kind of thing so wonderfully possible and easy without any middlemen anyway

Firstbits at the end of content imo.

Might as well both.

I don't fancy phone so I don't usually think of it.

What happens if you are watching on your fancy phone and the qr comes up, do you need another fancy phone to take a picture of it?

You need a QR capable device, which could be your phone or a dedicated reader. Btw, upgrade your phone because you're losing allot of useful features, besides, look around and you will see almost all of your peers having one  

The QR is usually accompanied by the text, so you could type it in if you happen to watch it on the same phone.