It's the defensive versatility. He plays more positions decently than most guys (who usually only play one or two decently). It's a plus that he's so disposable (and therefore always getting reset to major league minimum). And it's an American League thing, when you don't need pinch-hitters and you carry more bench/DH guys who can't field, that opens up a spot for an all-glove type.
Last year things just kind of fell together for him because of the Indians' injuries. And, for Cleveland, both times, he hit at a slightly more tolerable level.
In the end he still hasn't actually played that many games in the majors during any given season, and has now been waived four times in the past 12 months. If he actually could hit just a little bit that wouldn't happen, and he'd be making a couple of million a year by now.