When he has familiar practised phrases to say, Tyson doesn’t stutter as much and having everyone working on a script makes it even easier for him to avoid stuttering entirely. On top of that, when addressing a large audience, Tyson is even more confident and comfortable speaking, having been groomed to do exactly that since birth.
He doesn’t enjoy acting per say, having to use it in ways that make his skin crawl to think of to survive and for the needs of the web, but when he can completely separate himself from the performance, Tyson can see the appeal. He needs to give himself completely to a role, to a single moment for that to work, and Tyson can’t afford to have such a narrow focus when working.
He found it much harder to perform in rehearsals than on stage. Tyson could still hit the required notes, he always does well under pressure, but it would take him a long time to psyche himself up beforehand and afterwards his nerves would be completely frayed.
Other than hating himself enough to never give himself a break or give up on a task started, there was no reason for Tyson to force himself through something he didn’t enjoy and affected him so badly every time.