People mainly have multiple wallets for security. Therefore, if one wallet gets breached, they don't lose all the coins.
Maybe that's one of the reason why people have so many bitcoin wallets, they are thinking about their
security. And it is hard for each transaction to them to be traced if they have so many wallets or maybe
they just want to try different kinds of wallets.
agree with you, but we must not save bigger amount in 3rd wallet like coinbase or xapo, i think save bitcoin at paper wallet is good way , you can redeem it when you need bitcoin