Of course in the bank you only get 1%+ every year but in the crypto world you can get more than 500%+ within months or a year.
But don't forget that bank interest is way too less risky when compared to altcoin interest , yes 500% is possible but even loosing everything is highly possible.
Success and failure both are part of life. Even in regular currency there is a high risk of losing everything. So this point is not much to be highlighted because it involves luck factor and the way how wisely you invest your money. And is on its way to replace the regular currencies so no worries about losing.
In the term of profit i think yeah cryptocurrency is better than regular currency but in the term of usage both has their own impact.
We need both crypto currencies as well as regular currency to co exist at the same time because there are a lot of transactions that take place through regular currency compared to crypto currencies.Also Many places crypto currencies are not accepted so it becomes mandatory to use regular money so, both are dependent on each other and no one is better than other.