Even if the bill passes, a big portion of the unbanked population will remain the same, since the internet penetration rate in Mexico stands at roughly 74% only and I have a strong feeling that most Mexicans with incomes below the poverty line, probably wouldn't use something as volatile as BTCitcoin either.
This idea may not have the immediate solution to all of the Mexican economic problem but it's a good option for now instead of just relying on the old banking system. Besides that if the bill passes, it will be headlines for alot of media out there and some other countries will also consider the same idea for their country