Why create Kiosk accounts on connection server instead of AD?

I'm somewhat confused on why it is necessary to create Kiosk accounts in the connection server rather than just directly creating in AD yourself.  The connection server creates an AD account but what else is it accomplishing?

You can go in and manually create a "custom-*" account and use it with Kiosk mode and it appears to work just as one created on the server would.  The only differences is now you have to manage the accounts also from a second sources.

What am I missing?

Thanks,