The average wage for most kind of hard labour is around ₹200/hour or ₹600/day in cities, which will be around $3/hour or $10/day. I believe the bigger issue is the payment system rather than money, most Indians don't use digital payments

Nothing. For poor it might make them think for a few seconds, but its still nothing.

The real issue is they can't compete with $0.

Also best way WhatsApp can work around this is to just ship their app with the phone, and bill the phone $1 * avg life of the phone.