No I do not work at Blackstone. I have collaborated with them multiple times and got a lot of data from them for writing my normalcy article. I visited them and wrote an article on how they process UOAs.
UOAs are tools. If you understand their benefits and limitations, and use them correctly, they can be very important in helping making good decisions in your maintenance program. UOAs are a direct view of lube health. They are an indirect view of equipment health. Nothing more; nothing less. They can be used to confirm/deny suspected issues such as leaking injectors, coolant intrusion, etc; if you have no reason to suspect these issues then UOAs are not a necessity.
There are a bazillion cars that can run for hundreds of thousands of miles and never get a UOA. No one "needs" a UOA to ensure the vehicles live a long healthy life; simply following the conservative OEM schedule will do that. If one is interested in managing the maintenance program to maximize the ROI, for any product chosen, then UOAs are the best tool to get you there.
However, when folks pay for UOAs, and ignore the data by not adjusting their maintenance plans accordingly, then yes, they are a waste. In this vain, they become a toy. That's not a popular thing to hear, especially at a website full of lube zealots, but it's the truth.