It's a bad idea teaching old people to use bitcoin. Mostly old people in my country don't know how to use cellphone or computer. But if they knew, what will be in their mind if you introduce bitcoin to them? In news, bitcoin always mention because in our country many investment scam use bitcoin as their mode of payment. Old people always watch news, and if I'll introduce it to them they'll avoid it and think that it is a scam.
I think it is not a bad idea.
It is just that most of these old people are a fan of the government, telling them that something like a Bitcoin that is centralized and not controlled by the government could raise suspicions to them telling you their theories and even ludicrous claims against Bitcoin and cryptocurrencies. I kind of experienced it so I immediately stopped. Some might find them interesting but most of them would just don't care and may find it suspicious.