Investing as the concept have nothing to do with the people who give money to the banks. The banks normally serve for savings (for whom who want to have more money/bitcoin using the amount have) and for investors who made the opposite of the savers (take money from the bank to create a business).
Naturally the money can be taken from the bank from everyone and not only for doing business but if is talked for investing the bank serve for giving money and for having money.
As for investments online these have nothing to do with the banks. I haven't heard any kind of bitcoin online bank who take bitcoin to everyone promising interest for them and give them to the others in order to have bigger interest from the lasts (which one must be so big that can do the bank to earn itself and pay the interests to the firsts).
I have heard and I am user (and earner of good profits) of sites which take your bitcoins, work with those and make profit for those and for the person who give money.
As for being secure no one can be never sure about investing online (every kind of investing). So who invest must know that exist the risk that one day the website may disappear and with it even the money/bitcoin invested on it. So invested doing all the possible analysis and deciding case by case. Anyhow there are factors which give much security (always having in mind that are online opportunities). I have three of those from which I am earning very good profits since three months. Who is interested to give a look pm me.