Great write up, and I appreciate your focus on why we build prototypes in the first place.
I’m new to Framer and turned to it as a means of responsive prototyping as well. After going through your article and the code examples you provided, I will say that WebFlow is probably comparable in terms of the amount of time it takes to create a prototype. WebFlow does most of the responsive refactoring for you—even allowing you to change typography at different breakpoints. The code created by WebFlow is quite clean, and could be used in production (another huge time saver).