Those withdrawal contains several transactions. The fee is lower for every single transaction.
And important part - you pay fee for withdrawal in tokens.
You can take a look on:
This looks like depositing tokens to the L2 on mainnet. I have to agree, the Storj Labs will pay this fee to deposit STORJ to L2, but they will deposit a noticeable amount, so t should be acceptable.
The fee of L2-L2 transfer is small. And will be paid by Storj Labs too.
The fee of withdrawal from L2 to L1 will be extracted in tokens, not ETH (and you can select another token to pay this fee). This is mean, that you do not need to have ETH on L1 or L2 address to receive tokens on L1.
The interesting thing, that you can specify a different address for withdrawal, i.e. deposit of exchange for example.
So, the zkSync is only way for SNOs, who doesn’t have an ETH on their wallet yet.