I'm not 100% sure if we need it or not, that's part of the discussion. I am immensely curious what reasons you would offer against it, besides not wanting to change Bitcoin unnecessarily.

As for my reasoning, it is widespread knowledge that the seasons are connected to economic activity, which seems to be a pretty strong justification (i.e. economic incentive) for the alignment. For a counter-example, what business accounting office would ever want to adopt something like the Muslim calendar that rolls through the tropical year? Q4 would never have it's proper meaning in such a calendar.

Besides the economic incentive, we humans have a natural seasonal "sense" for time, and it will always be more natural to earthlings to do their scheduling and accounting accordingly.