I saw that too...How can something using Electron be highly efficient? Maybe they are talking about the interface and not the system resources the app uses.
This player: http://gqmpeg.sourceforge.net/mpeg-over.html
With a library of 5,011 songs.
Consumes 18 mb.
Since it uses the CLI mpg123 binary to actually play the songs, when playing the child mpg123 process uses up another 3 mb.
So take your pick, 18 mb or 21 mb. Much lower resource usage either way.
edit: missed a word