Inflation is 2%-3% or more in most countries and could go higher. The banks don’t pay that much in most countries. Since 2008 and 0% interest rates, many people have indirectly lost over 30% of their money, as this loss to inflation compounds.
Have you also noted that in those countries internet penetration and smartphone usage might be low too, making the use of cryptocurrency low too?
That is the basic drawback that crypto has, in order to run it you need a working electricity supply, internet and a device. Of course you need that to transact and you dont need it to invest for the long term where you can safely store your coins in a wallet for years hoping to sell at some point.
People have their own reasons of investing or not investing and you cant change that. Telling someone to buy bitcoin you are more likely to get punched in the face because their country might not be lenient towards it. This may change in future and exchange companies are doing a lot of work trying to get the youth involved into promotion and use of crypto. All this will take a bigger turn if major merchants start accepting crypto.