For bitcoin at the moment you have to move around $1300 before the fee is less than 0.2%
And around $2400 for etherium. Which means that in the common use as a payment it will be more expensive. On top of that you get into questionable situations if the shop owner wants to charge differently because of the fee as that is already disallowed for plastic cards.
That statement makes no sense. Crypto transfer fees are not a percentage of the transferred amount.