Udemy, Coursera, Steam and many other international websites already accept RuPay Domestic cards since last 3 to 4 years.
Few International payment gateways already supported RuPay Domestic cards, they debit INR currency from RuPay Domestic card and convert to other currency and send to merchants.
Recently i saw Epik website tieup with Razorpay to accept RuPay Domestic cards and debit exactly USD to INR coversation rate without any extra fee.
Note - RuPay Domestic card means payment proceed through RuPay's own 3D secure gateway like Paysecure/BEPG network instead of Discover's ProtectBuy or JCB's J/Secure™.
NPCI also recently release a circular, instructed banks to enabled International payment for all RuPay Domestic cards by default.