I think it's about catering to as wide an audience as possible.
If 60% of people will eat animal fat cooked chips, that means that 40% won't. The reality is that if folks want chips then pretty much 100% will eat those cooked in plant oils.
Whether it's a moral or health or just personal choice doesn't matter...the 100% of customers is the bit that does.
Unless the kitchen makes a feature of being 'traditional'......and let's be honest, this is the UK, it's only recently that rapeseed oil has been chemically treated well enough to make it edible by humans; there was only animal, fish or fowl fat here in the past centuries.
Now we have sunflowers growing in Wales, rapeseed in Scotland, but I don't think we're really producing olives yet, not enough for oil.
I managed to keep two wee trees alive for a few years, and they did produce handfuls of fruits, but the hard cold after a wet day killed them.
Commercially ? doubtful.
So, fats. Eat sparingly, eat well