Walker lines up at RB, FB, H-Back, TE, OL, and wide-out. On any given play, he could go deep, run an out, take a hand-off, pass protect, run block, or block down the field. He does none of these better than anyone on the team, but he does all of these skills well enough to be an asset. He'll have bad games catching the ball, but I like him getting targets anyways because it forces defenses to have to account for him.
And that's the point of his versatility: he is one of the best tools we have to deceive defenses. I think that we, as a team, value him and utilize his diverse skill set more than other teams would.
That being said, he's not vital, and we could upgrade the TE2 position if Walker chases money in FA.