To get the best flavour and texture and make them as close to the original as possible, vegan butter is necessary. My recipes are all about getting the best results possible.
With every recipe I publish I get requests for oil-free, gluten-free, grain-free, fat-free, paleo, whole-food, nightshade-free etc options. I don't have the time to test every possible variation of every single recipe so I generally make what I like best and what will appeal to the majority. It's physically impossible to keep everyone happy.
I do offer oil-free options in quite a lot of recipes though and I have an oil-free section in my recipe index: https://avirtualvegan.com/category/oil-free/

Miyoko's (which is the brand I link to) is a 100% vegan brand. I wouldn't recommend anything that wasn't vegan.