If I decided to save bitcoins in bank, how will deposit rate be changed compared to dollar or other currencies? Will it have much lower percent?
Its sad to say but there are no bitcoin banks existing online.
Wow this isn't true! There are several bitcoin banks online - Coinbase, Circle, Xapo!
None of these banks offer interest on savings. They don't have to. It doesn't make sense for them as a company to offer interest. The reason fiat banks offer interest is because they use the savings to give out loans with that money - the interest on the savings is always less than the interest on the loaned money, the difference is their profit.
Giving out loans with bitcoin is very difficult, it's risky, since the the transactions are final and somewhat anonymous. So the online bitcoin banks don't offer loans, therefore there's no need or incentive to pay interest on savings.
The benefit online bitcoin banks provide is the extreme ease of accessing the bitcoin market. It's so much easier than trying to convert fiat to bitcoin via other methods.