I don't quite understand what you exactly mean by me being wrong
When I open a deposit in a bank, the bank sets the interest rate which it will pay on my deposit. Whether it is going to sit on the money or reinvest it, I pretty much don't care as long as they don't scam. I can't possibly see how this type of investment is different from any other investment, apart from a fixed interest, of course. On the other hand, it is expected that the bank would be loaning my money to other people and earning profits, part of which it will share with me
So some people think they will lock the money in a safe, keep the money safe and there it will wait for your return. but banks do not do that. not even if you ask them to. Banks do not store money, they invest your money. the only way to store money in a bank is to put cash in a deposit box in a bank. for that you pay instead of getting an interest rate.
Most people think they put your money to good use, like loaning it to other people. But sadly this is wrong again. And here comes a thing called fractional reserve into play. let us say you deposited $100, then this means that they can give someone else a loan of up to $1000. they take your $100 and just make the other $900 up. They act like they have more money then they really have. This is a scam to me, but it is legal. So even if someone asks only for a loan of $100, they will not give them your $100, but take $10 of your $100 as reserve and make the other $90 up, so they can loan out $100 and keep your $90 for someone es who is willing to take out a loan. They do this because this is how they make money. They create money. They want you to take a loan.
Here is something i like: let us assume you want to buy a car and need some extra money to afford it. You go to your bank and take a loan to buy the car. As insurance for the loan you bank accepts your new car. This means you get money from the bank and pay the seller of the car and the car is yours, but if you fail to pay back your bank then your car will become the banks car. Why does the bank not just buy the car from the seller and you pay the bank until you have paid the full price and the car is yours and if you fail to pay them, then the bank owns the car. This can not be done, because the bank does not have the money. Only by taking out a loan they create the money. And by creating money they earn money, so they want you to take a loan.