I'm pretty sure a big goal is to fight tax evasion.
I can't speak for all of EU, but here in Austria tax evasion is very common.
For example, it's still extremely common to pay contractors under the table. They will ask you if you need an invoice, and the price will be a lot lower if you don't.
Another example are restaurants. For a few years it has been required that restaurants always provide you with a receipt, but especially asian restaurants still don't do so.
All that untaxed revenue costs the state billions in missing taxes.
If you limit cash payments, then you make it at least slightly harder for someone to eg. buy a car with that untaxed money.
I really don't see any reason why you would need 10k€ cash payments if not for tax evasion.
I have not seen a SEPA wire transfer cost more than 1€ since SEPA wire transfers have existed. Which would make the fee at most 0.01% for >10k€ payments.
The most that I have ever payed is 1€. I have been paying 0€ for the last 5 years or so. Is that still a fee?
"Oh lultimouomo", you say, "the were transfer might be nominally free but sure having a bank has other costs involved". No fixed cost, yrgulation, so by the very fact of having a bank account, depositing money in it and taking it back by wire transfer or ATM you are never paying a fee.
Also, cash has a cost. You risk being mugged, you risk getting a wrong change by the cashier, the store risks a robbery / break in (and most often pays expensive insurance to protect itself against this)
Not sure why you are getting downvoted. The government of cyprus did seize bank deposits during the 2013 crisis. In some european countries i spoke to people who worried the same will have happened during the onset of covid and then the war started by russia.
I can't speak for all of EU, but here in Austria tax evasion is very common.
For example, it's still extremely common to pay contractors under the table. They will ask you if you need an invoice, and the price will be a lot lower if you don't.
Another example are restaurants. For a few years it has been required that restaurants always provide you with a receipt, but especially asian restaurants still don't do so.
All that untaxed revenue costs the state billions in missing taxes.
If you limit cash payments, then you make it at least slightly harder for someone to eg. buy a car with that untaxed money.
I really don't see any reason why you would need 10k€ cash payments if not for tax evasion.