TIL that in 2020, Burger King ran an advertising campaign featuring a picture of a moldy Whopper, to prove that their burgers are made without preservatives. This unconventional advertising method worked, increasing sales by 14% (according to multiple sources.)
They technically have preservative properties because of the hydrogenation, but they really aren’t used for that purpose. You don’t fry things to necessarily preserve them better. It’s for taste/texture, like you said.