Why preboot

[WWS]

I remember way back even before Classic FDISR had the archive feature, in the 'help' instructions,
it told you to disable preboot before making an image.
Then it was concluded that you didn't need to disable preboot before making an image.
And ever since, I've never disabled preboot before making an image, or for
any other reason.

And I've never had a problem with re-imaging or booting to re-image.

I see in a post of May 2011, "samy" had to reinstall FDISR to get his
preboot re-enabled.

Question is, what would be a reason to disable preboot in the first place?