Why would it be daunting to create a readme? At least, why would it be any more difficult for someone new to things that downloading, installing and running an app?
A README is meant to be a detailed document that describes what a project is, how to install it, and how to use it. It also needs information on things like how to contribute to the project. That can be a lot to think about, especially for a beginner who is still working out how to make their project work. One can end up putting a lot of pressure on themselves unnecessarily when thinking about everything that goes into a document like this. Having a nice boilerplate process takes a lot of the guess work out of the process and makes it more achievable to great something useful to others.
What I guess I mean is, why does it help for this to be an app, why not just a template Markdown or text file?
I think because it is more interactive using an app. Interactive tools are fun to use. Also with a template you could miss some fields, not with a tool that asks you for the informations.
With a template you could add sections as you need to for future projects without forking and hacking someone else's app.
I agree with Nathanaël. Interactive tools can be very effective in making sure one doesn't miss things or at least knowingly skips them. Like when starting a new project with npm init it is helpful to have an app make sure you get everything right from the start.
But, this isn't for everyone. For some folks it may be just as easy to have a repo with all of the starting points they need. Now that Github has template repos one could easily have this setup in their account and use it to get going on a project.
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