You can cheat with some userscripts, yes (double check and reorder scripts in particular are notorious for getting misused). But that’s generally not what they’re designed to do. I personally really like them and probably would not have gotten to level 60 without them because I think they add a lot of value to the site (there are many scripts that only add additional content and don’t alter core features), and they can help facilitate more flexibility and consistency with your study plan.
All of the scripts that I use(d) are in my level 60 thread if you want my personal recommendations, though there are many other scripts out there, too.