You know that banks and gold are good to invest for long term. Your banks investment will earn few money interest within a year/s, it is safe investment though.
Your gold investment is safe as banks for both are stable investment.

If you invest in cryptocurrency the higher risk because of unstable movement of market. The chance to win higher profit than gold and bank investment in a short time is possible (know as quick rich especially in bull run), the same to lose in a day(drastic fall). By the way it depends on what kind of your crypto investment.

In some time there are circumstances and unexpected situations in cryptocurrency but why need to believe that it is good investment?