You are correct-- typically Coinbase is used to directly buy or order bitcoin, not to transfer money from your bank account into it.
But the way I would be getting USD into the account is by transferring BTC and then selling it for USD. At this point Coinbase would be holding a sizable amount of my USD fiat on their service. I just want to know if this is safe in a volume of $10,000 or more.
Previously, I have typically bought my bitcoins from exchanges and then quickly sent them to my personal offline btc wallet to get them out of exchanges fast so that no matter what I'm safe. But this time I want to wait to buy bitcoin until I feel the time is right.
Is this a safe idea? Or am I missing some risks here that I should be aware of due to the volume of USD involved sitting on their service?
Any personal bad experiences, or does this quantity seem safe enough?
I'm trying to tell you that unlike an exchange, you don't have a fiat balance at the vendor. The balance is in YOUR mainstream bank account. So the basis of your question about whether it is safe to have Coinbase sit on your fiat until you decide to buy
is not valid. I just logged into my Coinbase account again to look around, and I see nothing which would indicate that I'm mistaken about this.
Of course Coinbase has some transient cashflow issues to deal with when you make a sale or purchase of BTC. How they deal with that and mitigate the risks is their own secret sauce.
As you've probably notice, many people here claim that Coinbase games the risk mitigation to skim profits when there is volatility, but it would be hard to prove, and most of the people making the assertions have little solid evidence to back it up. I would not rule it out, but I've never felt that I've been abused. But then I've only used them with me being in seller mode (around $25k in the last few weeks.)
Nobody has claimed that Coinbase flat out stole money. Only that they canceled transactions in instance when it worked against the user's favor. If there are cancellations when it worked in the user's favor we would probably hear less about them on this board. But if the price is generally going up, and most of the cancellations happen when the user is trying to buy, it is logical that most of those who have been effected have felt that they got screwed.