Agreed for the most part, but might not work in all cases. For eg. Learning to use vim ....

Well, I learned vim by building something (using vim).

I just sucked it up and ran vim, then ran head first through the brick walls... That was years ago, and I'll never regret it.

Yes for some cases building something will not work,but not on this. You should make things like plugins, edit configuration files to learn the full use of vim.