AFTERTHOUGHT:

The 'what if' construction is also useful when we don't expect an answer!

"I told you NOT to go near the edge! What if you had slipped? You would've fallen down the cliff!"

"What if there are sharks in the water? You won't want to swim in the sea then!"

Thanks for your clear explanation!!!
It's very interesting...

Thank you for your words of appreciation for the help that the Grammar Monster team have been.