This is a Canola Oil vs. Coconut Oil thing, not cans vs. bag-in-box. Coconut Oil has very high levels of saturated fats and is solid at room temperature. Canola Oil is low in Saturated Fats and is liquid at room temperature.
My popcorn experts tell me that the taste of popcorn popped in Coconut Oil is more rich and satisfying. I used to use Coconut Oil for years. Now I am using Canola oil and I like the flavor of our corn. I find it just as satisfying. Both theatres use real butter.
My personal experience indicates that working with canola oil is much easier. I'll never go back. When we used to run out of oil during a rush, it was always a pain to put that heated pump in the can. It would take 15 minutes. The theatre had a poorly ventilated room that got hot. We kept the cans in there so they would be soft. Now when we run out we just put the pump in a new can and we are ready to go.
Both oils are expressly made for popping corn and contain yellow dye to make the popcorn look good. I once ran out of oil and went to the store to buy regular un-dyed canola oil and the corn came out white. Some people told me that week that it was better than ever, but it sure looked strange.
It's like 2% milk vs. whole milk. My mother only bought 2% milk because I drank a ½ gallon a day and was tending towards chunkiness. When someone gave me whole milk, I thought it tasted like cream and didn't like it. If you give your patrons popcorn with canola oil, they will get used to it. Most will say it taste better because it is lighter tasting. Some will miss the richness of Coconut oil and ask for extra butter. OK.