I really see them as usefull only on very expensive morphs.
A 'possible 50% het' has a 1 in 2 chance of being a 100% het.
A 'possible 66% het' Has a 2 in 3 chance of being a 100% het.
If I buy a 100% het male, and a number of 'possible het females', best case I have the possibility of producing the morph in the F1, worst case I produce '50% possible hets' of my own.
A 100% het piebald ball python can run as much as $4000.
From a business view if I can afford 5 possible het females each with at least a 50/50 chance of being a 100% het for the price of 1 or 2 100% het females I can in the best case wind up with 5 100% het females and produce numerous of the morph in the F1, the flip side is I wind up with no het females until the F1 generation, but at a minimum investment. For most other non-high end animals possible hets are of little interest except to the individual breeder and basically run the same price as normals with 100% hets running a little more.