I think it's a good idea to use more than one bitcoin wallets.I use 2 wallet for security purposes. many people get hacked.
If one wallet website get hacked, you have another wallet as an backup.
Yes its mainly because of security and i use two wallets as well.One is block.io and one is blockchain.info wallet and distribute my bitcoins equally amongst both two wallets.Even i dont have much bitcoins,but its important for those who are carrying a bigger amount of bitcoins.