Forget the binary choice between including or ignoring local events in destination selection; there is a third way that prevails.
The real question is not whether an event is important, but why we travel in the first place, which gives a completely different meaning to planning.
Many of my patients who travel for specialized care ignore local festivals; their priority is access to medical expertise, not the atmosphere.
For example, coming to Japan for a unique surgery makes the Gion Matsuri a distraction, not a decision criterion, the deep goal of the trip being paramount.