Living expenses have to come from somewhere. If you use the time to graduate faster, instead of working to generate weekly income, in some cases you can come out ahead overall. Details vary, but it's not obvious that it's a bad deal.
I think most students in America have loans. For me, and everyone I knew, there was a credit balance after the school got paid and that money was put into your bank account.
Don't forget you have to buy books, etc., and they cost "a couple of hundred dollars" too.
When I was an undergraduate I was definitely on a knife's edge, but I also often had cash in the bank because I got a big cash infusion annually. I just had to live off a very strict budget at that time to make sure the money would last.
I wouldn't have wanted to rely on this service when I was a student, especially at that cost, but in a pinch I could see situations where it would make sense.
> It's weird because CMRR is listed in decibels but it's absolutely a DC spec.
If you get the Franco book equation 5.27 (my edition is the 3rd) explains why they do that. Long story short: It's a convenient form when CMRR = dVcm/dVos due to the orders of magnitude involved.
Technically you probably could do it externally in most cases but it would require a bunch of extra stuff, and be a pain, so usually it's best to use the stuff built into the amplifier itself.
On CMRR, in some mathematical treatments it's modeled as a change in offset voltage with respect to common mode, which indirectly effects output voltage of course so at the end of the day it's the same result. (See: https://www.google.com/books/edition/Design_With_Operational... highly recommended )
It's also odd that the 741 was dismissed, as it should be, but the TLV9301 was not recommended. This part is specifically called out on TI's 741 page as what to use instead in 2025. Not only does it perform better in basically every possible spec, it's also a drop in replacement for most, if not all, applications.