You have a point, because if you put it all in just one wallet and for example you have paid someone, your bitcoin address would show in the blockchain.info showing the amounts of bitcoin that you have in your wallet, and because of greediness, they will do anything to steal your bitcoin and take it all without you noticing it. Having this kind of idea is really a great one, though you will need a lot of wallets for you to divide your bitcoin to be safe on someone's greedy hands.