I just looked through there website and I fail to see how it would be quicker or better than spinning up a quick rails app with a bootstrap template. Most of my time developing is thinking about the domain model and workflows. Once I've decided on that it takes a matter of minutes to code features and then you are not restricted in your ability to adjust and enhance after the fact.
I think there's a lot here that even as an experienced engineer I hate to start doing from scratch. Now combine that with time to focus on the business
* Where to deploy?
* Where to store the code?
* Which library to send emails with?
* Which 3rd service to send emails with?
A long time ago I spent 2-3 weeks building something to do all the above. After completion, I started going to customers and realised those 2/3wks were basically wasted time because I could have just put a google form and would've done just as good a job. Except now you get something a bit better than that.
If you can solve your issues with a google form then use a google form. I would never start a simple project as an app. All my coded projects are more complex than that. Some might be able to be done with no code tools but it would definitely be a pita to execute.
Your approach requires learning HTML, CSS, Bootstrap and Rails documentation in order to create a prototype.
You may as well be saying that getting furniture from IKEA isn't any simpler than buying lumber, saws, wax and paint from Home Depot and building your own.
I already know all those things and learned them for pleasure. Once you know it, nocode vs code is like the difference between using a GUI with a mouse or learning the keyboard shortcuts and using the command line. GUI with mouse just slows you down and is less flexible in general. Fine for lots of things but it's hardly a substitute for complex apps. Nocode apps are basically approximations.
I use nocode tools all the time, just not for building products. They’re great but they are also limited. If you hit any kind of success with your prototype you have to be ready to do it for real.
Having that background is what trained me to be able to think logically like you do to build systems which is the hard part. I wasn't born knowning this stuff either. In fact I only learned it properly in my late 20's.