coinbase works just fine for me breh. Perhaps you didn't pay your internet bill?

Clearly I was referring to a temporary, although serious issue if you need to access to sell off and the site crashes because it's overloaded with other people trying to sell off.
The 24/7 trading nature of Bitcoin is also a problem. Web sites need to perform maintenance and require down time. There have been times where Coinbase did or at least claimed to need downtime right in the middle of a huge sell off.