The same is true when selling. Once you have Bitcoins back on Coinbase, you sell and Coinbase will move USD back to your bank account. One less step for buying and selling than you are showing.
The selling part is what I'm concerned about since isn't there a potential lag between having my Bitcoin on Bittrex and its finding its way over to Coinbase?
With that in mind, I just checked out cex.io as recommended by john2231. Assuming I do a bank transfer (free), wouldn't this exchange make more sense than the process I described? I'm now wondering if Coinbase/GDAX are *really* meant for folks who are just interested in BTC, ETH, LTC while other exchanges are geared towards people who want to dive into different alt coins...
I've never used cex.io so I can't give any advice on that.
Cashing out at Coinbase: If you have altcoins on Bittrex, you would need to convert them to Bitcoins first, then send them to Coinbase, then sell for USD and Coinbase will put it in your bank account.
You do have to jump through a few hoops for these transactions. I keep some funds in Bitcoins or altcoins so I don't need to do these conversions. I did at first to originally buy the Bitcoins and did a couple of sells.