Is there any down-side to making a form (used to enter data) a member of a user created class module?

For example, the class module maintains a collection (dictionary) and has add, edit, & delete methods. It seems as though more data could remain private if I can copy the input data directly from the form (a member) to the collection. Am I thinking too much?

Starting to get confused, . . . or would it make more sense to make an object of my class a member of the form? . . .

John