Drink it many days a week, but not all. Usually 1 cup.
Over the years I've used BPC I've kind of adopted a "less is more" approach to the grass fed butter, often using less than a tablespoon. I definitely prefer MCT oil, or Asprey's Brain Octane branded MCT oil to straight up coconut oil in BPC but if I don't have any on hand I do like to use coconut milk/cream from a can. Sometimes I prefer that in my coffee to the butter.
I'd say I get about 100-200 calories from my coffee on a regular basis.
I also like to add in other stuff like cinnamon, cardamon powder, and unsweetened cocoa powder. Usually just the cinnamon and cardamon though.
Mark Sisson makes a strong case for egg yolk coffee or "Primal Coffee" as he puts it. He feels that as good as grass fed butter is, pastured eggs are a better source of fat and nutrients. Here's link to that. https://www.marksdailyapple.com/primal-egg-coffee/
I like the egg yolk coffee as an alternative to the butter, but it's way less convenient to crack open eggs and temper the yolks so they don't scramble, on a regular basis.
There have been some periods where I'll drink multiple cups of BPC, getting anywhere from 400-700 calories from the fat, but those are usually days when I don't eat much else as it does curb my appetite significantly.