Because such a company would need to be regulated. I'm not against regulation, the problem is that once you get regulation you also accept to use the legal currency exchange rate, which is expensive for most use cases.
Let me provide accurate, real-world examples:
- 1 USD = 171.276 ARS (according to XE's website, this is the official exchange rate).
- 1 USD = 311.25 ARS (according to Binance's P2P exchange, this is the parallel/black market rate).
In Argentina, most stuff is valued in USD, even if the legal tender is ARS. If you were to buy a $2500 ARS burger with Binance money, that burger costs you $8.03 USD. If you were to buy that same exact burger with a licensed properly regulated exchange, that burger costs you $14.59 USD, almost the double.
This might seem like a trivial example, and a few dollars don't seem to make much of a difference. Try the same example with your weekly grocery store basket, rental apartments, payments of a car, etc. It all adds up and most people here don't earn more than $300 USD monthly (valued in black market exchange rate, of course).
Plus, Argentina and Venezuela are heavily taxed.
EDIT: Formatting of the example.