I was never a huge Tate Martell backer but I understand why they're playing him and why they'll continue to play him. He makes the defense adjust to him. His presence on the field means the opponent must be extra cautious of a potential trick play. He may not be the most gifted natural passer but he's way more of a threat to throw the ball than any of the other receivers. Watch some of the replays from the UF game. Especially Dallas' touchdown run. He goes in motion and their whole defense keys on him. At the snap, two UF defenders immediately head towards him, clearing extra space for Dallas to take the Wildcat snap and go straight to the house.
Obviously, he's not an every down guy but as long as he's a major distraction for opposing defenses, he's going to get 10-15 plays a game. I especially like having him on the field in Wildcat formations. Most of the time, if a team has their quarterback on the field for the Wildcat, he's just standing out wide, not doing anything. You're essentially playing 10 on 11. With Martell in the game and Dallas lined up as the Wildcat QB, you actually have to defend him taking away the numbers advantage.