Circle's maximum is $300/week so they are useless.
If you use Coinbase, do NOT use them as a wallet.
Buy and then move them elsewhere.
Otherwise Coinbase will eventually ask you to account for every withdrawal/deposit you've made.
What do you mean that Coinbase will eventually ask you to account for every withdraw or deposit?
My statement was probably unintentionally exaggerated - they probably have a certain total USD/BTC amount of deposits/withdrawals.
When you reach that, it's exactly as I stated: They will demand you account for where you sent every withdrawal, and where every deposit came from.
They do that as their interpretation of KYC ("Know Your Customer") USA banking regulations.
If you do not comply you are barred from using their services for buy/sell.
There is no warning of this beforehand, and they can request this long after the dates of your deposits/withdrawals.
So much for the "anonymity" of btc.