PSA: use only #2.
If you *really* need it, put a warning comment for #1.
Avoid #3 (unless you're generating code), and for #4 use Number rather than an easy-to-miss unary operator.
Totally agree with you. The only one that would make sense to improve readability is the numbers separators.
Mostly the idea was that you can do these things in JS, not that one should do them :)