Are they alone? Can't they learn things? Literacy is something we can learn regardless of age. They may only be illiterate but they can still understand things. They just need guidance therefore, they could still benefit from cryptocurrencies the way we do, like no differences at all but it would depend on their will to do so. With benefits, it could be profit by means of investment, alternative mode of transaction and payment, and more.
What are the benefits of cryptocurrency to the illiterate people?
There's no benefit. It is better for illiterate people to be taught to read first. In my opinion, it is unreasonable for anyone to think that Bitcoin can be an investment for those who are illiterate. Meanwhile, even normal people have a big risk, especially illiterate people will have difficulty finding technical and fundamental analysis about Bitcoin. Their risk would be greater than someone who can read and I don't think it's a good option for them. I know bitcoin is a good technology but not all good things are accepted in all circles
But not all literate people are into investments right? What's missing to them? Definitely will and it does not require literacy in the first place. They COULD benefit from this industry and as you said they just need to learn things first. But there are ways and that is if there's someone to guide them with things. Risk is understandable by all people by the concept of 'gambling'wherein everyone is aware of. Athough things are different between investment and gambling, the thought is simply how risk is manageable.