You can actually interact with some crypto projects over SMS, and at the moment there are countries where the majority of txs are SMS mobile credit swaps. The issue is these don’t offer things like account histories, you can’t access financial products like loans (i.e micro loans) and remittance payments are hard to do from abroad in this way.

But actually smart phones and internet access is surprisingly high in sub Saharan africa where they primarily still use SMS trading.

And yes, crypto is starting to catch on out there as an alternative.