Need an advice from the HTML Templates Authors

Hello everybody,

I’m going to create new HTML themes for selling at themeforest which will be created with SASS & Gulp & Pug .

Is this technologies will be useful ( as feature ) for the HTML templates customers as it make the customizing easier ?

and which one won’t be useful and customers hate it ?

Thanks in Advance

I should suggest come with the basic CSS first and check the sales. If it goes well, you can add SASS and more as a new feature later so you wouldn’t be wasting your time.