Let's get this out of the way: you're not trying to become a designer. You're a builder who wants to make products people actually enjoy using.
The difference:
Designer: Spends 3 weeks perfecting a pixel-perfect mockup
Builder: Makes smart design decisions that ship in 3 hours
Both are valid. This course teaches the builder approach.
Good enough design that ships beats perfect design that doesn't. And with the frameworks in this course, your "good enough" will be better than 90% of indie products.