Richie, I think you missed the point entirely.

Acoustic guitars are harder to play! To learn classic guitar to play electric guitar also makes no sense.

It makes a lot of sense if you understand that a 9-year-old or a 14-year-old may not be completely formed as far as the music they will enjoy for a lifetime and what they may eventually choose to play. The parent or teacher who advises learning the more difficult instrument is allowing that child to have the range of instruments in their future. Just because the electric guitar is easier to play--why go straight there and thus exclude easier access to more complicated instruments later? Go back and look at the discussion in the thread I linked to in my first contribution here. There were a couple of folks who said they wanted to go from electric to classical in their later years but just couldn't manage the transition. Each week I sit through my son's lesson and for a few minutes visit with a grown man whose lesson follows his, and who is attempting to learn classical after originally learning electric. "It's really difficult" is his regular mantra, and he is a bit discouraged--with a full-time job and not enough hours in the day to practice like he would want, he isn't certain that he can move successfully to the more complex instrument.

Once the skills are in place they can be (pardon the slur) adjusted down to play the easier instruments. I advise you to be more proactive in your teaching--teach music, don't just teach songs. Aim high, and encourage your students to think globally. Then they, too, can accumulate various instruments like Sting has with his lute. And don't forget the sitar. Learn music well in relation to this stringed instrument and you can do lots of interesting things. Learn the easiest instrument because it is charismatic and you pose unintentional limitations.

SRS