Ok, it's like keeping cash in your mattress, safe, safety deposit box, wallet, personal vault, whatever.
The point is it's your responsibility to secure it, and if you think you can do that properly then great. I can do it, but I don't think it's easy enough that most "normal" people can do it properly yet.
You being responsible for the security of your assets is the price you pay for having total control and ownership, just like with everything else. Putting money in the bank or PayPal reduces the risk of theft but increases the risk of bail-ins and account freeze. There is always a tradeoff.
Bitcoin offers a lot of security mechanism that are not available with traditional asserts, like m-of-n-keys etc. Insured online wallets will become available as well.
The point is it's your responsibility to secure it, and if you think you can do that properly then great. I can do it, but I don't think it's easy enough that most "normal" people can do it properly yet.