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Every smart people should have different wallet online, that is to minimize the risk as we cannot see the future, it could be stolen and all our investment are gone, you do not call it a savings instead so it is just good to diversify it.
using multiple bitcoin wallets is not really "being smart" you can have only 1 bitcoin wallet and be the safest possible. i believe you should call it paranoid instead of smart.
making a secure bitcoin wallet which is always offline and stays that way is not really hard, and i am talking from 2 years of experience with having only one bitcoin wallet on an offline linux system.