The difference being that, functionality-wise, you don't get anything from using Atom over, say, Emacs or Vim. High memory and CPU utilization is a tradeoff I'm willing to take for the added benefit of running IntelliJ or Visual Studio, because as environments they do way more for certain code bases than either Vim or Emacs could do. But Atom? Not so much. "It's made of Javascript and HTML" is not an advantage (to me) worth the memory and lag.