People applying for jobs often say "I don't have experience with technology X but I'm really interested in it.".
But they haven't downloaded it, played with it, built a sample project with it, or written a short blog post about it or tweeted on it or whatever. So they aren't actually interested, they are "conceptually interested".
Often there's a long cover letter explaining the excuses for being conceptually interested rather than actually interested. The excuse is usually lack of time to be actually interested.
Being conceptually interested is mainly useful for applying for jobs and is quite different from being actually interested.