Post covid it would have made sense, the bookers seeing his songs hitting the charts and thinking that he's a solid artist.
I think today's bookers realise that his songs only hit the charts because of his tik tok skits popularity, and a booking that high will take credibility from the festival.
How big are the rest of Williams shows? The Newcastle venue has never had a stadium sized capacity but if he’s playing it may open up the gates for more big named acts playing up here.
More likely Fender is one of them.