The main problems with bitcoin is that its hard to understand for most people, need to have cyber security knowledge to transact it and its prone to orchestrated attacks.
The common challenges with bitcoin are the value of cryptocurrency is not stable, it fluctuates either too high or too low. We have to be brave enough not to panic when the price is dumping.
Also, it is not easy to secure the money you earn from bitcoin. Like what happened to my two friends when they are about to transact their savings in bitcoin but its already gone. Their savings went for nothing.