I think it's because women haven't integrated the technology yet. Please let me explain :)
Women are high consumers of luxury goods across the world. The luxury goods market was estimated at more than $400b in 2020, and increasing. If you take into consideration the fact that a large portion of these transactions undergo banking fees at around 2%, that makes more or less $8bn of revenue turned into smoke, which luxury companies lose to banking intermediaries.
The two main reasons why these companies agree to pay banking fees is insured transactions (the buyer pays with a credit card then fails to reimburse the bank) and convenience (most luxury goods customers carry more than one credit card with them).
Pseudo-DeFi offers a good replacement to the first cost (insurance). However, first, most luxury clients actually don't need the credit card: they simply cannot pay easily without pulling out a bag of cash (and look like crooks) or use a credit card.
Second, crypto payment is not yet convenient: we need to offer women an attractive, portable and easy to use wallet mechanism that can easily withstand loss/theft of mobile device, easy to top up, and in the correct cryptocurrency that is accepted across luxury brands. Think of it as the iPhone problem: there were many smartphones with a touch screen before the iPhone, but none of them looked attractive.
Once luxury brands solve this problem (or Apple, I can easily imagine Apple solving this problem, because 94% luxury clients have iPhones), in my opinion, crypto payments will take off worldwide and there will be no looking back. They will reduce costs to both sellers and shoppers, which qualifies quite well to the "why" question.