While examining the fee structure on Kraken I noticed the following peculiar pattern:
Ethereum:
Deposit Minimum: 0.05 ETH (approx. $61.99 at time of posting)
Deposit Fee: Variable on-chain fee to move into Kraken's wallet
Initially, I thought the rationale behind the minimum deposit + deposit fee is that it represents the total (avg) cost for Kraken to move a deposit from a user's personal deposit address (which is uniquely generated for each user to track their deposits) to a central "consolidation" address.
However, further down I see the following:
Tether USD (OMNI):
Deposit Minimum: 1 USDT
Deposit Fee: FREE
Tether USD (ERC20):
Deposit Minimum: 1 USDT
Deposit Fee: FREE
The cost to perform an on chain transfer of ETH tokens such as USDT (ERC20) is significantly greater than the cost to transfer ETH itself - yet Kraken is actually charging you nothing to deposit USDT (ECR20) (while also allowing you to deposit extremely small amounts of the token) whereas it is charging you the standard blockchain fee to deposit ETH itself and enforcing a much higher min deposit.
Is there something I'm missing about how gas is paid in the ETH blockchain that might explain this peculiar behavior or is it a purely business decision made by Kraken? If it's a business decision then I'm not asking for speculation about why Kraken might have taken this move. However, if it's a decision that has roots in some fundamental difference in how fees are charged/paid for ETH vs ECR20 tokens (or perhaps something else makes it easier to move around ECR20 vs ETH) I am interested in understanding this.
UPDATE: What I'm really trying to ask is whether the premise of the question is correct (i.e, that there's nothing in the Ethereum ecosystem that makes this move rationale) Or whether this move could be explained by something related to how ETH transactions/fees work. So my question is not so much about Kraken but whether or not something like this could be explained from a ETH transaction/gas fee perspective.. Hope this helps clarify..