A new product aiming for large-scale adoption needs to be ten times better than existing solutions, meaning it must have a significant advantage in terms of scale.

The biggest limiting factor for crypto payments is foreign exchange fees, which are even worse than those of current payment solutions because of the additional crypto-to-fiat conversion costs.
The reason for high foreign exchange fees is "currency sovereignty." Governments do not allow their merchants to accept US dollar stablecoins directly, nor do they permit residents to use stablecoins for widespread payments.
Fundamentally, crypto payments do not improve the core scenario of currency exchange compared to traditional solutions, so they are unlikely to replace the existing payment systems on a large scale. Instead, they will persist as a niche market in the long term.