From a capitalist economic perspective, it makes logical sense to maximize your profits and entice wealthier customers with quantity discounts.
From a societal impact perspective, it adds transactions that may not have happened otherwise, but these are mostly isolated effects from what I can tell. This can spur the economy with spending, and be more efficient. Ultimately however, it ensures that those with more money and the ability to buy in bulk lose less money than the tired masses. This should lead to wealth inequality over time.
Without knowing what impact each of these individual variables has in isolation, it’s difficult to define metrics for “net benefit” to society with any real certainty, let alone begin to measure them.
Only those transactions at the higher volume tier get the higher discount (and everyone is eligible for that same discount).