Yup, I guess I should just be a bit less lazy and give a bit more context for each section :)

Some things are just personal preferences and some things are just completely subjective. Overall, though, these advices tend to make front-end code better. The JS part, for example, is largely based on functional programming best practices. Things like immutability, statelessness and the point about JS performance aren't subjective: they'll basically always improve your code's quality.