as i know virtually nothing about "body work", i think i would use the bondo recommended for plastic.
my thoughts on this is, regular bondo would not expand and contract the same as the glove box door, thus breaking the bond between the repair and causing cracks to re-form. how long this would take to happen, i don't have a clue.
the bondo for plastic should share the characteristics of the glove box door material much better, making for a longer lasting repair.
just my thoughts on this matter.
your mileage will vary.