Forget the binary between duration and cost as decisive factors of a trip.
The real problem is not whether a two-week stay is better than a longer one in low season for budget reasons, but rather what we want to experience.
Here in Japan, seasonality is intrinsically linked to experiences like cherry blossoms or summer festivals, making date flexibility often impossible.
Trying to save money by shifting a trip to see sakura in low season is a contradiction, as the event is ephemeral and fixed.
The lived experience, even if brief and more expensive, takes precedence over financial optimization, like buying a ticket for a specific art festival.