Yes. In fact, it's the term you'll see used more often than others, such as, "tech addiction", "technology addiction" and "screen addiction". "Internet addiction" and "smartphone addiction" are not as generalized in their sense but far more common. Other expressions used frequently in this context include "the digital drug" (not to be confused with the literal term), "internet obsession", etc.

Lol not a common phrase. People who use technology allot we may call them tech savvy. But otherwise I've yet to hear digital addiction in any common sense.