Agreed. It’s so good it feels like it should have been that way all along. For example, when you view the help for a function Emacs has always given you a link to the source code where that function is defined. Helpful shows you the source code right in the Help buffer, and shows you a list of callers, and gives you buttons that enable tracing or debugging for the function.

Once I discovered Helpful, all of those things seemed so obviously useful that I can’t understand why nobody else thought to put them there, including myself.

The best part is the forget function, for when functions are incompatible. As an example, lsp won't work for me unless I forget the project-root function from ess-r (I have no idea why this hasn't been fixed) and helpful makes this a two or three key activity.