Context first: does the impact of local events on travel planning truly have a universal influence, or does it vary greatly depending on the market and type of trip?
Here, in Portugal, for some, the São João Festival in Porto is a major asset, while for others, it's just a period to avoid because of crowds and prices.
A traveler seeking tranquility might find that an event, even if culturally rich, is more a constraint than an opportunity, especially if their budget is tight and they are looking for local prices.
It seems to me that searching for events is a crucial consideration for some very specific types of stays, but not an absolute rule for all trips, especially those focused on relaxation or exploration off the beaten path.