ah ok, so what i meant was that you are not mixing a record to sound good on one source, but on all of them ideally, and you are correct when you are saying that it´s important that a song sounds great on headphones. That doesn´t mean though, that you can rely on the lowest common denominator for the whole production process, especially mastering an album, which sets a lot of the tone as well. Spacing of instruments is another great example, where headphones lack.

but in reality, whats the harm really, when a lot of hobbyists make that experience themselves?

In case of op, if he doesn´t believe my opinion (and why should he really, i´m a trucker from minnesota and deaf in one ear XD), worst case is, he just has a pair of nice headphones, before he realizes he needs to spend more money if he wants to get serious...