the best intel that I've gathered is this: coinbase has already bought Bitcoin, Eth and Lite, so they've got it there on hand and they just makes us wait. On a day with a big price drop they weren't going to release "their" coins at a price less than what they paid, they then blame heavy traffic. My guess is they are arbitraging too. I was on a live chat and some of the traders recommended Gdax, I haven't research it yet. Exchanges and Wallets are the weak links for me. I don't know if this is factual, but it seems on volatile days, when we can either buy bargains or sell before the stampede, CB is useless...