McDonalds was egregiously horrible throughout the trial which is why they were hit with punitive damages. "Granny" wanted $20k for the medical expenses of an eight day hospital stay and lost wages. The jury watched McDonalds consciously weighing more than seven hundred reports of customers with medical injuries against others customers having a hot cup of coffee at the end of a long commute and saying they would live with people getting 3rd degree burns.
Also, even if your coffee is merely warm, rather than hot it's still "drinkable." If you are some coffee snob who wants a really perfect hot cup of coffee, you aren't drinking the swill McDonalds serves.