Features:

3 states of blocking: full blocking (blocking internal and external scripts too), half blocking (allowing internal and blocking external scripts) and no blocking
single click operation
automatic page reload
utilizing Firefox's Sync feature to remember and auto restore settings across devices (version 53+ or local storage only)
compatible with desktop and mobile platforms

Pushing functionality from server side back to the users by running more codes on their computers instead of on the server is a tendency where the industry go and so web sites use more and more resources on the users' devices so their battery may go off faster. The other problem is that websites and web services become more and more vulnerable for cyber attacks using cross site scripting and other techniques. These can be solved with this extension with some trade off. Turning off scripts on websites might break functionality. However if some of them use heavy scripting making your device slow or you worry about being hacked through that site then it is a good practice to block scripts if you want to visit them anyway. This tool is just an option for you. There are other more sophisticated options like using the NoScript extension which is a great piece of work that gives you better security because it can block scripts before loading at all whereas YesScript2 blocks them after you activate it by clicking on the icon. However teaching your browser for every domain and every script calls with NoScript seems a tedious and long work. It varies to whom it's worth it. If it's not you then YesScript2 might work for you better. One of the main priorities when writing this extension was to create a small code set so it can be audited much easier making it more trustful. The less lines of code, the more reliable and secure a solution can be. I'd also like to express that I find the original YesScript extension a great idea and a nice work. This is a complete rewrite of it because the developer did not intend to continue development. This has nothing to do with the original in any way except its purpose. Thank you.