FWIW, I use Coinbase, and it seems to be a competent and well run company, even if it is suffering from massive growth pains.  And I think this massive growth they are experiencing is indicative of the future, where they are positioning themselves.  They do have alt coin trading, as any good well run business should, but I don't think it is a distraction as much as just offering the most for the customer which they cater to.

I doubt they will have the resources and time to waste with possible bad investments.  Their "Vault" even seems to be a relatively safe way to store BTC, even though I keep mine in off line cold storage.

The big picture of BTC may be hard to see, but the periphery of the industry, as exemplified by Coinbase, is showing the stress of what could be massive growth and expectations.