For the first question, Cryptocurrency is already a personal financial support system so the future you are talking about is obviously here as we all have seen the performance of some cryptocurrency especially bitcoin because it has really performed with an unimaginable speed so there's no need to doubt it's future anymore.

As for what i will do with my crypto asset when i get old? Isn't it money we are talking about here? what more can one think of at old age if not handing over your wealth to your children to continue in your legacy.

For the third question, besides bitcoin, i don't have any alternative coin that i can trust and have confidence in same way i have for bitcoin so it's either bitcoin or nothing else.