I learn loads of stuff just for fun. Its super interesting to learn detailed specifics of topics, especially knowing you're never going to be tested on it.

Mostly that I just find learning new things fulfilling.

I want to design accelerators for Fintech applications at some point soon, hence the FPGA and Finance courses. As for the Manufacturing one, in my eyes I need to understand to full breadth of the industrial chain. Perhaps not as deep as obtaining raw materials (mining/chemistry), but understanding how we turn raw materials into useful tools is something that's important no mater what kind of engineer you are.