It's true that there's a double-edge to it. The new advantage being that books became an extension of ourselves. Having access to printed knowledge meant we didn't have to memorize every line (and after all, we've come to learn that understanding certainly does not equate with wrote memorization). We can have a working memory of what we need to know on a regular basis, while retaining "pointers", or knowledge of where knowledge is, for the rest of it. I'd wager (without doing any proper research on the subject) that we're largely more effective, and cooperative this way.

The difference between books and smart phones is such that there are a theoretically limited number of ways you could use the book. You can partake of its knowledge, memorize it as an exercise, rip it up, burn it, draw all over it, etc etc. But for the most part its main purpose is its primary purpose.

Phones as they are called, aren't so much phones anymore. They're a complete mobile computing system. All of publicly accessible human knowledge is at the fingertips of whoever has one with a live connection to the internet. You can do just about anything with them, abilities dependent.

I remind my girlfriend of this all the time as she's lying curled up on the couch playing candy crush :P