Petition to crypto exchanges: enable paying for withdrawal fees and other fees with a fiat currency (if the user chooses this as a preferred method) to simplify capital gains reporting

Please enable an alternative way to pay for the withdrawal fees (with fiat currency instead of paying with cryptocurrency).

Paying for any other fees (like exchange fees) would also be useful if the user can select which way to pay (there should be settings "pay all fees with specific fiat currency" - with a drop-down menu to select the preferred fiat currency; if there is no balance in that fiat currency other currency in the list will be used).

Context:

Paying for fees with cryptocurrency triggers a tax event. It's like buying a candy with cryptocurrency.

For this reason, I propose cryptocurrency exchanges to allow payments in fiat currencies for the fees instead of paying in cryptocurrency (if it's preferable by the user).

For example, the fee for withdrawing cryptocurrency on-chain.

The fee for the transaction is not a big problem because always the capital gain/loss is zero (because it's paid at the same time as the order is executed).