As a student of psychology I think the following are the biggest problems in the cryptocurrency market,
- Price Volatility- If you can't go on a trip for 2 weeks without wondering if your BTC is $20K, or $6K or $8K then you can't trust it as a store of value. There is no store of value with such wild swings.
- Trusting Exchanges- Recent hacks or scams such as Nicehash, Coincheck, Bitgrail etc degrade 'trust' that their funds can be stored online. What is needed is insurance for online exchanges, but that brings regulation, taxes, and oversight.
- Adoption- The first 2 problems limit adoption. I want to use crypto for my coffee, my gas, my car and my house, but I won't anytime soon until these problems get resolved.
- Scalability- This is the 4th problem, not #1 like alot of experts put forward. Scaling is not a priority until adoption picks up, and even then exchange fees and block time confirmation lag are both bigger problems.