

For a lot of distro’s you don’t need to use a terminal to install things if you aren’t comfortable with that. While I believe learning to use a commandline a little bit will always be beneficial, you really don’t havo to. Take a look at linux mint for example, which has a “store” for packages.
I don’t think it would be anymore. Modern compilers are really really good at what they do, and often manually optimizing(writing assembly yourself) makes programs slower. So unless you are very good at assembly, I would just trust the compiler.