The principle is .... Bank makes money from you. So if you think you can make money out of banks, then you must be more naive than the banks.
Having said that, it doesn't mean you cann't make money WITH the banks, together with them ...
Unfortunately due to banking history and its old pratices, they will hide everything they think is benefiting you. ( btw, before there are moneys, there are already banks ). Although they are regulated by goverment to protect you, but they still have the room "Not To Voluntarily Offer You Information".
With Banks, if you don't ask the right question, you will NEVER get the right answer.
So all the traditional banking products including Saving Accounts and Fix Deposit just let you get by. You don't really earn anything from there if you consider inflation. In the past, Banks didn't want you to know about Mutual Funds and Insurance. But now they don't have that choice anymore.
In short, you put your money in Saving Accounts and Fix Deposit when you don't know what else to do with them. AND you think its higher risk to keep them in your own place. If someone stole your money from your place, you lost them. If someone stole your money from the bank you deposit into, usually you will still get your money back, thanks to legislation and laws.
Inflation => You Lose(Saving Accounts + Fix Deposit) - Inflation -> You Lose LESS
But you still don't earn.
(don't assume yet, mutual fund and insurance aren't going to get you out of your rat race neither, if its that simple, I wouldn't need to start a blog at all)