It's significantly faster than most other dynamic languages. It's fast as a compilation target to the extent we can run Unreal Engine in the browser. So I consider the original comment I replied to that simply stated 'Bad performance' incorrect or at least lazy/contextless criticism. If you want to reframe, fine, but I'm not going there :)
Accidental string coercion is a valid point. Also hasn't bitten me in ~10 years of building large JS apps. And JS has many advantages over e.g. Python these days that to me vastly overshadow that downside (better support for FP for one).
(And if you really want that type safety you can use TypeScript, just another great thing to come out of the JS community, you know the one that GPP criticised for daring to provide choice).