Coinbase employee here. We're providing the bridge between finance 1.0 (e.g. banks) and finance 2.0. This means we're subject to requirements of the banking partners we work with and can only support merchants within their comfort level.

Unfortunately there are times when we would like to support a merchant but can't, but its a hard thing to keep the bridge open. You can read more here: https://medium.com/the-coinbase-blog/building-the-bridge-why...