Wow, that's interesting. I've been using Coinbase for almost 4 years now. I retain an average balance of usually around $500 in BTC (obviously depending on the market) but I never touch that and i simply purchase the crypto I want to send moments before sending it. I've made a ton... well hundreds anyway, of transactions this way, but I always purchase the BTC via my actual bank account or most often with the debit card attached to my bank account. Never had an issue and the fees are minimal.
I have, also in the past, easily transferred my Coinbase assets back to my bank after converting them to cash. It's been awhile since I've done that though.
Shit. Sounds like it's time to rethink my haphazard way of sending payments out.