Remove rust inside door panels?

I use readily available napa rust convertor from napa auto parts.

I guess that's one thing I'm unsure about - the rust converters actually DO convert rust to something stable, or are they more or less a cover-up or encapsulation chemical? I know I could Google it, but most of what I have seen are obvious promotions of Brand X or whatever, fewer are actually endorsed by non-sponsored users who actually enjoy it.