thank you guys, that make sense now.
1) If i send USDC token from kraken to coinbase wallet (not coinbase, but its wallet app). It just cost me $2.5 and done.
When did you do this? Is this a fixed fee? As Bin mentioned above, your 2nd transfer needs gas (unless I misunderstood what you mean by 1st and 2nd wallet) and since Ethereum is busy as hell atm, paying $10 or more should be expected since you're interacting with a smart contract, while your first transaction is likely paid with batch transactions. In short, your first transaction is just one of many transactions that likely pay more than $100 or so, but each user get a tx fee and that's why the exchange still makes profits.
just yesterday, it's a fixed $2.5, i understand why now. Love kraken everything is so much cheaper than coinbase to transact on