Business class doesn't need to be consistent across the entire Amtrak system, all it needs to be is better than coach class on the same train.
This is true of airlines, too. Last year (before the virus), my Dad flew out to the west coast to visit my sister. Since he turned 90, he's decided to spring for first class. His outbound flight had a lie-flat seat cubicle, even though it was just a 6-hour transcontinental flight. His eastbound flight had a (very roomy) reclining seat. He didn't say too much about the food service, except that, of course, he was served a meal, unlike the poor suckers in coach. So even with the airlines, first class isn't always the same product.
In general, Amtrak business class is superior to the coach class on the same train:
My experience in the east
Northeast regional -- BC has Amfleet 1 BC 2x2 car more legroom and window curtains. #65-66-67 have the 2x1 club seating with leg rests, though I think the leg rests are useless.
Carolinian, the same plus an attendant comes and hands out drinks. Except that means you can't get your free drink whenever you want in the cafe car, you have to wait until the attendant comes around.
Vermonter and Ethan Allen Express -- BC is the 2x1 club seating, coach are Amfleet 1 corridor coaches.
Pennsylvanian and Palmetto -- Amfleet 1 BC car, but Amfleet 2 coaches in the consist (along with Amfleet 1 coaches.)
The trains where BC is not substantially better than coach are the Pennsylvanian and Palmetto. Of course, if the Amfleet 2 coaches are all full, which happened to me once when I rode the Pennsylvanian, you'd be better in business class as compared to the available Amfleet 1 coaches. Nonetheless, I ride business class on the Palmetto, because (as least on Saturday northbound trains), the business class never fills up, and I get a seat pair to myself all the way from Savannah to Baltimore, whereas the coaches are packed.
I sure take advantage of the free coffee or soda, but but a free $2 coffee really isn't the reason why I'd upgrade. It's mostly for more space and a better chance of a seat to myself are the main reasons. The 25% AGR TQP bonus is also good.