Sorry for the plug, but I can't help myself everytime I read about task managers to notice you have to learn yet another DSL. DSL are the plague of our field, for one that is useful like SQL, you have a hundred that turn your life into hell. Make's DSL is already full of gotchas, but templated YAML based DSL are just insanity. They have so many footguns, and so little flexibility and ability to be debugged. After try…
I guess that could work for a Python project, where you already have Python installed. But still you would need to set up a venv or similar to keep your system Python clean. Then you cannot run the tasks without creating that venv or similar. How to create the venv and install all the correct dev dependencies into it? You can't use the task runner yet, because you still need to install that ... Maybe a Makefile?
Having to install doit first is indeed going to be a barrier of entry for a lot of people.
It's still worth it in my experience, but I get how it can deter users.