sadly, there are few people who don't believe in cryptocurrency technology advancement that is changing the world as we see it. There is not much you can do about them except guide them to proper resources that brings them knowledge about cryptocurrency and how it has helped bring some of the biggest change in the financial system. At first, people won't care about it but that's only step in. Even if they come in as a trader, they will be inclined to learn more about it in the future as it advances.