This is nice initiative and any attempt to make mathematics more accessible is a value added to society in my book. However, saying you will learn "mathematical thinking" by watching 1.5 hours of passively watching, even Professor Tao, is quite an overpromise. I don't think there's a subject that requires more hands on practice and thinking than math, especially higher level math, so this is more along the lines of edutainment. So in my mind, how valuable this course is depends on what this content replaces for you. If watching this series replaces something distracting then its great, but if it replaces actually doing problems and working out proofs, then it's not worth it.
Finally there's a celebrity aspect to Masterclass that's a bit strange. Like these guys are famous, and because they're famous, they are the most worthy to teach you something.
Some series you should check out that are free and IMO provide much better value for time:
Academy of Achievement: https://achievement.org/
* Some good lessons with Eric Lander, Larry Page, Sergey Brin, Bill Gates, Jeff Bezos and Demis Hassabis
3B1B: https://www.3blue1brown.com/
Numberphile: https://www.youtube.com/channel/UCoxcjq-8xIDTYp3uz647V5A