>So how is that better than having the control itself tell me what the problem is?

You can put all your initializing validations in one spot of the form, and then have the form abort at that one spot.

If you just fail to show the control, you may miss it in testing, with the ASSERT, you'll know cause it will slap you in the face.

You don't have to have the control tell its container it failed, like what you were intially asking, the container will know.

You don't need the debugger for ASSERT.

ASSERT is a one line command that gives you a messagebox with several debug options.