To my knowledge, Business Class on the Starlight is the only example of a BC product where pleather seating is the only real benefit of the hard product. Though even that isn’t guaranteed.
On all the other routes, BC offers somr mix of onboard vouchers, complimentary beverage(s) and/or snacks, legroom, seat width, window curtains, and so on. There is no real rhyme or reason why some routes offer a BC product that is absolutely worth the cost and some are arguably complete ripoffs, but that’s the way it is. IMHO, the real issue is less the inconsistency in and of itself, and more that Amtrak does very little to distinguish the different variants and make the benefits (or lack of) clear.