The problem with two overlapping timelines
Owning a house in the place you left is expensive and distracting. Mortgage, taxes, insurance, and upkeep continue while you are establishing yourself somewhere else, and a vacant home is harder to keep an eye on from a distance.
The alternative many sellers dislike more is accepting a contract they are not comfortable with because the moving truck is booked.
Choosing the date first
In a direct sale the closing date is part of the conversation rather than a consequence of when a buyer's loan clears. If you need to close before a start date, or need extra weeks to move out, say so early and we will plan around it.
We can also discuss a short period of post-closing occupancy in some cases. It depends on the property and the specifics, and we would put anything like that in writing.
Downsizing and family changes
The same applies to a move into a smaller home, a senior living community, or a move closer to family. Where the property needs work no one wants to manage from a distance, an as-is sale removes that project from the transition.