Meh, depends on the exact usecase. Tweens work perfectly fine and in the end also run on the same math essentially. It can be useful to understand the math behind, but not required.
I have to agree with you on this one. I've been making more and more use of tweens for various animations, special effects, etc.
It all achieves the same result, but tweens can get you there at a faster. Nothing wrong with that, and also having an understanding what is going on behind the scenes. Even if it is only a basic understanding.