Code:
class modules are a must
Admittedly, I didn't go into property let or createobject as I didn't want to get too complicated. Okay, yes you're right that they're different to standard modules, but the reusable code is why they are there.

With your statement, I would say 100% that this is an option to be considered when designing the functionality and use of the program. If you have a 1 form calculator program, then the "are a must" bit doesn't always need to come into play and I have no idea what he's designing !