1. The classes were extremely expensive. I paid something like $1500-$2000 for one course. At the time though I was working so I had more money and less schedule flexibility, so it was worth it.
2. The class was actually really helpful. I forced myself to do my homeworks in LaTex to learn the language. The proofs helped me get in the mindset of first year micro, and the assignments were structured similar to my first year homework. I learned a lot about formal math.
3. The class required discipline. You could pass without learning a ton since homework and the test was all open book. There was not a ton of accountability which I guess is good practice for grad school.
Overall I think I had to take the class because my math profile was weak, but I also came from a high ranked undergrad program and had a few great letters so it's hard to say if the class hurt or helped in applications. My gut tells me that as long as the sponsoring uni is well known like Harvard or UMaryland it's probably not discounted. That's probably why they can get away with charging so much.