It's not stupid at all to fall in love with someone over the internet. As a matter of fact, you're getting to know their personality before their looks, so it would have a slightly better chance of being a better relationship.
However, it is dangerous.
What you need to worry about, is that they could be telling lies about what they're like.
More importantly, you need to know that it's a real person, and not just someone sending you old photos of past victims, and saying they're doing things as the person you think they are, while they're actually sitting in a chair eating cheese puffs and smelling funny.
As long as you know it's a real person, and they're telling the truth about what they're like, then go for it.
It's not stupid it all, as long as you're careful.