My grandfather wants to buy 40,000$ worth of gold coins because he believes inflation will boom in the coming years.

I think he has the right idea, but I believe Bitcoin would be a better investment for him. How can I help him understand the benefits of Bitcoin over solid gold?

Update: Thanks for all the replies, (most of) you all gave really solid advice. I won’t even bother with changing his mind other than having a conversation about Bitcoin and to see what he thinks of it.