...So, if there is no benefit to using a lithium battery, why are people making, selling, and apparently buying them ?...
The problem with your argument is you didn't answer the question. You only ask more questions that cause more confusion and bring doubts to your point.
If Southwest Space Agency gives me a free bottle of water with the brand-name Pure Spring and I paid $70 for the ticket and United Aviation would charge me that same bottle of Pure Spring for the luxury price of $10 after I paid $1,000 for the same destination ticket, so what's the argument about if I paid $1,000 ticket, why do I complain about $10 water bottle that's free in the other airline?
That argument is confusing and does not help to justify how a free water bottle would cost a luxury price of $10!
There might be a reason why a luxury price is justifiable but you didn't spell it out.
The best argument is to stick to the reasons why it's good to pay more for Lithium such as:
Lighter weight
Reliable
Temperature tolerance
Durable
Longevity
Less wasted time for replacement
Costs more to waste 3 lead batteries than just buy 1 Lithium battery...
By the way, if you search for "luxury" on the Tesla site, it's doubtful that Tesla boasts its cars are "luxury". They may call something "Premium" like "Premium Connectivity" but not luxury.
Thus, if you keep talking about the concept of luxury, you would confuse many owners.