So far so good with Coinbase. But they will temporarily stop accepting deposit on Aug 1 and I am not sure when it will resume. I just wonder where the rejected payout goes.
I have set up Electrum on my machine in case. But I do prefer Coinbase since it's only a few blocks from my office

Hi Kano, I wonder if the payout from Kanopool to Coinbase is rejected, what will happen to the payout? Thanks.
If Coinbase rejects your payout, then they are not accepting Bitcoin.
So you have a rather major issue with them then.
If you think they might stop accepting Bitcoin then don't use them.
As was posted a few days ago
The Coinbase transaction stoppage is only for a few hours. Supposed to be 4 to be exact.
Ya know, Coinbase covers all this in their
UAHF/UASF FAQ and that is better info than people just guessing about it.
In short they will temporarily suspend withdrawals, purchases, and exchanges -- nothing said about not accepting direct BTC deposits to wallets.