The Internet is full of fraudulent websites. It's full of porn. Email isn't as warm as a hand-written letter. Communicating online isn't professional. Etc.
Guess what, all those things were true but they turned out not to matter. You can do whatever else you want in a network that also carries porn. You learn to dodge fraud. Email is freaking convenient once everybody is using it, standards of behavior change, etc.
Cryptocurrency may be something or it may not. It's in very early stages. Even those who are interested have trouble following everything that is happening. But it's not even Internet-in-the-90s. It's Internet-in-the-70s. You can be skeptical about it, you can ignore it, but I don't see why someone would spend so much of their time being opposed to it.