why would i share details of my mortgage as a buyer to the seller of the house if I’m pre-approved?

this was listed on a real estate information site as an option to put as a condition on your offer for a home:
‘getting a suitable mortgage (include the amount, interest rates and any other figures you feel important);’

assuming I’m already pre-approved for a mortgage, why would i be incented to put details of the actual mortgage as a condition of my offer to buy the house from the seller?