Nope. It is not that simple. and certainly not that secure: You have to enter your private key every time you log into an app. giving the app devs a chance to steal your key - and if using a browser it also gets placed in your cache - which is another place it can be stolen from. there’s other ways too
Discussion
Of course there are. I was just stating a less obvious one. Privacy matches the price. When it was cheap, people send the coins to Mt. Gox thinking they're safe. Now they know better. 🐸