I can tug with 3 of the 4 dogs I trial right now. For Ember, it helps. Kai is the same dog regardless of what you do, but she is always on in agility. She's one of those that the agility is a reward. For Athena, she loves tugging, but I get the most speed out of her by picking her up and starting to rev her up outside the ring letting her watch the other dogs run. By the time she's in the ring, she is fired up and ready to go. Aurora does tug at home, but it is not what we do at the trials as it is not the routine that makes her most comfortable. She is the one who's been attacked. She is best if I'm personally interacting with my hands. She wants me to rough house with her. She is big into chasing, and agility is about chasing me. She gets her confidence for the ring depending on what I do with her before she goes in.
All 4 of these dogs will tug. They all have naturally had a lot of toy drive. However, I think it comes down to knowing what works best for you and your dog to get the most out of them that you can in the ring. That is what I do. I experiment and find what works for each dog to make sure running is as fun as it can be, and that my dog is as on as they can be, and ready to go out and run as fast as they can.
Now in practice, I will alternate rewards depending on what I'm working on. I can interchange a tug, throw toy, and treats depending on what I need to do. In fact, with my young Rebound grandson, Roxas, I use a lot of toy throwing and tugging. He was too focused on me, is super fast, extremely green (bad combo- ends up with dog missing obstacles and barking at me) so I am using very little food, and a lot of throwing and tugging to help reinforce obstacle focus in him.