So there is different opinion among people about Bitcoin. Some people consider Bitcoin as "criminal money" because it's often used on the dark web and helps criminals to get away with selling drugs and stuff.
Bitcoin is used on dark sites because transactions can be done anonymously. and because of this Bitcoin is very popular for many criminal activities. However, apart from being used on dark sites, Bitcoin is also widely used for good purposes. fiat money through credit card fraud is also used for many criminal activities like buying/selling drugs, buying illegal weapons etc. Would you call fiat money also help criminal?
There are also people who think that Bitcoin is a bubble that will explode and lose its value, so they don't trust it.
Even though the value of bitcoin decreases sometimes, its price always increases but you look at fiat money, the value of fiat money also decreases constantly but once its value decreases, it never increases again. so will people distrust money like Bitcoin?
It's probably because these people don't know how Bitcoin and blockchain work.
Bitcoin runs on blockchain technology but Bitcoin and blockchain are completely different things and blockchain is now being used in the banking sector as well. So to understand about Bitcoin, you have to study about Bitcoin itself.
And there is a third group of people who think that Bitcoin is used just for gambling so they don't want to buy it.
Bitcoin is used on gambling sites as it is a simple and fast payment method but it is a misconception that Bitcoin is only used for gambling and who said Bitcoin is only used for gambling. He himself knows nothing about Bitcoin