French fries are good as a side for burgers and sandwiches whereas steak fries are a good side for bigger meals imo. Normal fries are good just fried and salted, whereas steak fries can have seasoning and spices that make it taste better.
With that said, if I go to a diner and get a burger and fries and they give me steak fries, I'm gonna wonder what the forget they're doing.