If such legit merchant processors as Bitpay and Coinbase reject dirty BTC, why do you think any crypto transaction processor will accept XMR payments if everyone knows that XMR is widely used for dark deals?
The laws in every country are different and will impact the decisions of companies like Bitpay. If enough companies start to blacklist BTC then the acceleration to alternatives such as Monero will accelerate
In the field of AML/KYC/Anti-terrorism all countries laws are relatively similar, so don`t expect that big companies will invest in stealth digital currencies. So stealth currencies will only be used in dark markets which is a very limited frame of usage.
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