This assumes that insert-open-source-project works correctly and can fill all of your use cases. I think your right that many times it is a better choice to use a proven piece of open source software rather than build your own (e.g. using Blaze/React is often more productive than writing your own view layer). However, I’ve found that I often spend an absurd amount of time trying to bend some open source projects to my will (for even silly things like being able to put html in a form label with simple schema and autoform). Many times it is faster and more productive to build (or fork) a project yourself and develop a custom solution that you can reuse on all future projects. After building many a Meteor app it has made sense for me to build my own forms library and I really enjoy having total control over that aspect of my app.
I didn’t intend for my original answer to come across as a brash “just build your own” type answer. It’s just that my experience has shown that having a custom forms library has increased development speed and made my life easier. As a result, I suggested that the author consider it as an option now that Autoform appears to be lacking in support.