MS's JS engine wasn't very efficient (and probably still isn't, relative to the best implementations), but it has worked and continues to do so.
Yes, there are other JS server-side systems. I, personally, prefer class-oriented languages for server-side work. But that's me.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.