Butter is favored because most people had it in their youth. Some regions loves Nato and Chicken feet, others cheese and oysters. What's the most delicious? It depends of your own history.
I spread olive oil on my toast and prefer the croissants made with that as well. My favorite dish is fried tempeh.
Butter is NOT favored because most people had it in their youth, but because of its extremely distinct flavour.
"Unctuous" is certainly not specific enough, the reason butter (and ghee) is so delicious is its butteriness, i.e. it has a highly distinct taste. All properly rendered animal fats have highly distinct tastes and serve different purposes. Schmaltz tastes slightly of chicken, duck fat of duck, lard of pork, and tallow of beef.
But butter does NOT distinctly taste of beef, rather, it is reminiscent of slightly-aged milk (or, in the case of ghee, it may even strongly smell like certain kinds of aged cheese). There is, also, in butter, significant absorbed water content, and, to my palate, even a very subtle acidity that is not quite present in other rendered animal fats that give it a sort of brightness that make it work in things like butter-creams and other delicate or mild flavours (e.g. popcorn).
It is IMO this specifically "non-meaty" unctuousness that is the real draw of butter. Not some childhood nostalgia.
Wouldn't the preferred fat of a culture be spread between countries as they interacted then? Instead it has been fairly one directional with butter being adopted globally but other fats remaining niche (except Olive oil). Is that because of imperialism or is it because it is the best tasting one?
Today, I am one of the Ten Thousand [1] that learned you can make croissants with olive oil. Thank you for that! I've always assumed the laminated dough required solid fats, but apparently any layering of fat and flour can make flaky goodness. I am guessing that liquid fats are probably harder to work with, and croissants are already tricky enough to get right: but I must try.
Yes, lamination can be done with almost any fat, but the more you laminate (more layers / folds), the more that liquid fats sort of absorb into the dough, and stop having the desired separating effect. So while oil layering works well for e.g. paratha-style roti, scallion pancakes, and things that only really get one or two "layers" or "folds", oil is just fine. But when you get to something like a croissant, or even just a rough puff pastry (e.g. https://www.seriouseats.com/old-fashioned-flaky-pie-dough-re...), liquid fats are usually a complete non-starter.
You might be able to achieve something if you can somehow freeze your olive oil and chill your dough, and work very quickly during lamination, but you should, even with a lot of work and tweaking, still expect to get a noticeably inferior product for something like croissants.
Depending on how picky you are/not, you might still be personally happy with the texture and taste, but don't expect to get even remotely close to an actual good butter croissant, by more objective standards. Here in Canada we had a minor problem with the butter texture due to what we feed our cows here ("buttergate"), and this was preventing professional bakers from achieving quality croissants with just the Canadian butter. This should make you highly skeptical that you can get anything good with something as different as olive oil.
Still, I do love the idea of an olive oil croissant, it would be delicious.
Okay, so as expected liquid fats are much harder to work with and lead to an inferior flake. But, I assumed it was nigh impossible to do. If I can get 20% of the way there with olive oil I would be at least willing to try.
You can definitely get to 20% without much trouble, maybe even 30-50%, if you do some freezing tricks. Though what such percentages mean is highly subjective.
I am thinking if an ideal butter croissant has some flaky fluffiness (perhaps if we define it as "trapped volume" between flakes), and we define this ideal flakiness to be 100%, then you can extremely easily get to 20% with just olive oil. Frankly I think you might even get close to 50% (defined in this way) provided you also start with a trustworthy recipe by mass and that aims for proper hydration (e.g. https://www.seriouseats.com/croissants-recipe-11863500) and work quickly with lots of chilling.
Just, subjectively, you might realize that 20-50%, defined this way, isn't much like a proper French croissant, and is more like a cheap doughy supermarket chain croissant—which I do still frankly enjoy sometimes anyway!
Oily stuff tastes unctuous.
Butter is favored because most people had it in their youth. Some regions loves Nato and Chicken feet, others cheese and oysters. What's the most delicious? It depends of your own history.
I spread olive oil on my toast and prefer the croissants made with that as well. My favorite dish is fried tempeh.