Coinbase now supports the Bitcoin Payment Protocol
blog.coinbase.com
blog.coinbase.com
So destination address could be clickable in this. I think they should keep it underlined, though, personally. I guess even Google is throwing that out lately.
Is it just for payments where both sides use Coinbase? That sounds ridiculous, but that's what I see on the picture. And I still don't get which side needs to use Coinbase.
By the way, Bitpay already uses BIP70 - if your mobile application supports it, you just scan the barcode and the URL is included.
No it isn't. The user clicks "send with Bitcoin address", the same as they always have, in order to initiate this flow. Paying from Coinbase to Coinbase uses the other flow, usually.
URI method (what I'm used to from clicking a link to pay): https://github.com/bitcoin/bips/blob/master/bip-0021.mediawi...
If you are paying a Coinbase merchant from a Coinbase wallet, normally you wouldn't use this feature (since you can already log in directly and pay them).