You should never store any large amount of crypto currency in an online wallet. When you keep your crypto on a website (like in your Steem wallet or on an exchange) it is always susceptible to attack. I learned my lesson by getting bitcoin ripped off in the infamous Mt. Gox debacle- I don't even want to think how much it would be worth today.
You need to have a wallet ON YOUR OWN COMPUTER. I use Bitcoin Core. Keep that computer TURNED OFF unless you are using it to transfer crypto. Do not use it for routine stuff like posting or surfing the web. Use another computer for everyday tasks. Since you can buy a decent secondhand laptop for less than $300, if you have more than $300 of crypto you need to have a dedicated computer to store it on.
Steemit can't do it all. You must be smart with your crypto. Obviously the above is regarding crypto that you consider savings. Keeping your Steem in your Steemit wallet so that you can have voting power is another thing altogether. As far as I know, there isn't any offline "cold storage" Steem wallet. So until and unless there is one, all Steem is inherently insecure.