It was just for a short time , like 30 minutes or something. I think they had a big deposit or withdraw so for security reasons they decided to shut down the exchange until that transaction goes well ( this is what I'm think it was ).
No offense mate, one of the most "preposterous" reasons I heard so far. If this is true, then every time we're going to see them shutting down if we go by your reasoning? They should always prepared for this kind of transaction.
Coinbase has a strong good reputation and I can't see them doing something bad just because bitcoin hits 10k$...Bitcoin was last summer over 10k$ and Coinbase worked without any problems.
Reputation is subjective, but with the recent event, I think their reputation has been hit so hard and probably they are going to lose customers here.