I think an important distinction to make between STEEM and EOS is that most users who interact with STEEM do so via the Steemit / Busy application. Steemit takes care about the permissions to perform tasks on the STEEM blockchain.

EOS however is like an operating system where multiple apps are build on and a user need to take care about her/his permissions them self. For inexperienced users it is therefore easy to make a "mistake" and give owner instead of active permissions to the app they want to interact with.

So Steemit is definitely more secure for all kind of users simply because it handles the permissions part internally while with EOS you have more control but also greater risk if you are not careful.