In my opinion comparing Bitcoin with bank interest is not exactly the same. Banks pay interest because they use your money in various ways to earn money. But the main purpose of Bitcoin is not to provide regular income but to keep ownership of your assets in your own hands. However if someone is looking for regular returns by just keeping Bitcoin, then he will have to rely on some third party in almost all cases. To me this pretty much defeats the biggest advantage of keeping Bitcoin.
I totally agree with that, and I wonder why we are comparing Bitcoin with banks or bank deposits because those two are in no way similar, even if they have some similarities, there are so many differences. As you said, when we deposit our funds in a bank, it's not that our money is kept there until we withdraw or use it, they basically use the funds for investments and to make money with it, it could be giving our loans, buying and selling properties, and a bunch of other things that banks do to make money.
On the other hand, if we talk about Bitcoin, if we are just to buy and keep our bitcoins in our wallet, then our bitcoins basically just stay there, and over time, when its price moves up, we get profits without even doing anything, which is the biggest difference because you are not taking any risks or anything. Also, with banks and fiat currencies, your funds will lose purchasing power over time if you keep it for years and that thing doesn't happen with Bitcoin but instead, the value of your assets will eventually go higher.