The only difference would be if the fields are unstored calculations. If they are data, I don't think that it would make much difference.
For such a maintenance script, I'd use a layout that had the correct context but which did not have ANY fields on the layout....
so ... you are saying that all fields OFF SCREEN is not the same as no fields anywhere on the layout.
assume they are all stored text/number fields ...none are unstored calculations.
no fields is always better than some fields off screen?
I'm saying that it won't make much difference except for unstored calculation fields (or summary fields for that matter).
But leaving the fields off the layout makes sure that I don't have any unstored calcs, conditional formatting, hide object when now or due to some future change by my future self or a fellow programmer. I make it a blank layout except for bright red letters stating: "This is a utility layout used by script ABC...."