If you drink any specialty coffees, teas or like fresh-pressed juice, those will also go on your bar tab.
I consider us moderate drinkers and my sister-in-law and I had no problem spending $100 a day. But your mileage may vary. If you end up with too much left at the end of cruise, there are MANY posts here and on the VV Reddit, how to get it spent 🙂
So, the way the order of payment for drinks should go:
1) Bar tab
2) Any remaining sailor loot
3) Cabin account charged to your credit card at end of cruise
You can check it from the app so if there is a problem, you can go to Sailor Services and get it fixed. You should do this before you leave the ship. Easier that way.
Given the extra $50 for buying the bar tab before the cruise, personally I would do it.