Lets get rational and understand pros and cons crypto currencies... not just botcoin but beyond.

Major pros
Low few transctions(NOT BITCOIN)
High speed transaction(Not Bitcoin)
Massive ecommerce tool
Reshaping the industry and existing eco system

Major Cons
Black Money
Money laundering
Illegal activities
Volatile

Now lets dig into what a ban will achieve. Imho a ban will only take out the positive aspects of crypto and all the negative points are still gonna be there..
Like a person whos gonaa use it for illegal activities will use it regardless of Gov banning it or not I mean a ban will only take out Indian exchanges off of the game ban is not going to restrict blackmoney, launderinng or any other negative aspect but it surely is going to kill all positive aspects.