You need to answer yourself why exactly banks were created. The most common arguments are:
1. Because storing your valuables, money or securities in your house became problematic and harder. Banks are designed to be more secure for that purposes.
2. People were baited by small and secure income. After all people are earning a small amount of fixed interest by keeping money in a banks.
And with bitcoin both of these arguments are kinda obsolete. There is no need to place your bitcoin into a banking institution for safekeeping, because you can deal with it on your own.
Bitcoin can be stored, online, offline, or even on paper or carved in metal. Possibilities are endless.
Same with interest rates - so far no financial institution will offer you any amount of fixed interest.
In principle, I agree.
Bitcoin is a liberating technology mainly because it gives people monetary autonomy. But so far, i don't think the vision of being your own banks has been realised with 90% of bitcoin users (the percentage is made up and based on intuition so may be meaningless, even if it is accurate ). They still use custodians such as Coinbase (and HaoBTC too), which are little different from the banks. Either the technological hurdle is too high for average Bitcoiners or they are not mentally prepared to take full responsibility.
The same goes for interest. Everyone knows that in the long run, return is diminishing - there are only so many coins to be mined and difficulty keeps rising, but that doesn't negate the fact that within a certain time window, it is possible for people who are in possession of the right conditions to mine profitably, and this has been proven in the past few years by some Chinese miners.
While the principles are sound and inviolable, we sometimes have to be nuanced when it comes to the specifics.
for a good interest 
