It's zero forex markup fee, zero withdrawal charges (like Rs.200 in Fi Debit card).
But, SBI Yono app doesn't work in some countries (if you want to switch on/off international transaction, or change limits). Last week, the app worked in Vietnam but didn't work in Malaysia. Please google more on this.
Better to turn on int'l transaction before leaving the country and keep adequate limits.
PS: SBI website worked (only in landscape mode) and was difficult to use.