tips are for table wait service on the food only
Unless the staff are kick ass wine corner-sewers and able to impress me a lot....let me stop there, I don't like wine. I'll shift gears, and say beer-alcohol, as those are more likely to show up on my bill. Yeah, I'd tip to cover those, though they are notably less than wine. Especially considering beer-alcohol don't get on my tab but once in a blue moon, and even then it is only one or two drinks.
What I would like to add to the bit your 'expert' provided is that the tip is to be for the FULL amount of the food. So, when you've got coupons or some discount applied, the tip should be over the FULL amount, not the smaller amount. The restuarant is giving you a discount on the meal, the waiter didn't ask for or offer any sort of 'less service' in this arrangement.