When we can use sass/scss/less/stylus in this playground?

Answer 1

Good question, I think it would be a great feature!

Answer 2

Since those are a css compilers, you don't need them here, there a lot of people here doesn't familiar with these compilers and you need your code more understandable by anyone from biggner to advanced, you have to use it here in sololrean, but still a good feature to have when you needed it.