Is a consistent look actually a USP? I suspect there are certain hotel chains you can pick out a photo of its bedrooms from a random selection but I'm yet to see advertisement that says "Come to any XYZ Hotel as you'll love the consistent black & brass chinese style wardrobes"
There certainly are some where there are trends, as per the Luxury Collection often being in the old "grand hotel" but there are both examples where it isnt and many more examples where the old grand hotel is another chain (particularly when a city has several) which by default doesnt make it a unique selling point at chain level.
I certainly think there are trends amoungst chains, particularly in look/feel/vibe, but wouldnt call them USPs and wouldnt say they are all consistent. All hotels are influenced by their location and their local competition as well as brand ethos etc.