People are using so many wallets for their safety, if your wallet gets hacked they only make a little amount because your bitcoins are spread all over your wallets.
Yes that is why many people are using a lot of bitcoin wallets because they are going to be safe every time they are going to have transactions. And they are not going to be traced easily so that is why many are creating a lot of bitcoin wallets. And besides having a bitcoin wallet is only free so that anyone can just make as many as they can.