Why can't I put both products and sub categories in the same category folder? I know I'm not supposed to, but when I do it, it doesn't seem to cause any problems, on the contrary in fact.

I'm trying to make my main jewelery and lingerie categories display all the products from their sub categories in a random order (20 per page) in the same way all my other main categories do (my other main categories do not have sub-cats just products).

I can't figure out what files to modify in order to replicate this behaviour, but I'm thinking of just copying (linking) all the sub category products straight into the main jewelery and lingerie categories as linked products.

This would mean that there'd be both categories and products in the main categories. Again, I know you're not supposed to do this, but I've tested it and it does solve my problem. I can't see what harm it is doing, so can anyone please advise why we're not supposed to have both categories and products in the same category folders?