My understanding is it's mostly a thing in the northern latitudes -- England and Canada, and some northern US states, especially North Dakota.
In eg Indiana and Iowa the growing season is long enough there's no need to desiccate -- the weather isn't going to turn before the crop has a chance to dry.
Desiccation may also be used to deal with uneven ripening. Edible beans in particular are notorious for that problem. Harvest is generally in late summer, so weather isn't typically a problem, but by the time the late bloom is ready to harvest the early bloom may have already spoiled.
In eg Indiana and Iowa the growing season is long enough there's no need to desiccate -- the weather isn't going to turn before the crop has a chance to dry.