I think what Daryl is saying is, "First learn to play without a capo, then use it or not as you see fit".
Personally, I think a over-reliance on capos has kept many players from advancing as much as they could. An argument could be made the other way, too. If you have X hours available to learn to play (and we all have limited time), is it better to learn your licks fairly well in many keys or learn them extremely well, but only in, say, G, relying on the capo to allow you to play in other keys?
And, yes, they can play an important part in an advanced player's repertoire. But not everyone's of course.
One of the great benefits of using a capo, particularly high up the neck and especially if you use stiffer 'medium' gauge strings as I do, is that it effectively lowers the action and makes chord shapes easier to play - even if you play some barre chords away from the capo.
This has several advantages. It helps avoid strain injury if you play a lot on an acoustic; on an electric with super light gauge strings it doesn't matter. It also makes it a little easier for those of us who don't pick up the guitar and play as often as we should, helping to avoid overly sore finger tips.
The other thing is that a capo effectively shortens the scale length of the guitar in a way that a barred index finger cannot, and so changes the overall timbre of the guitar in a pleasing way, even helping to mimic other instruments such as a mandolin, if that's what you want.
My favourite capo positions are at the second, third, and fifth frets, all giving a pleasingly different sound to the instrument. When playing with a second guitarist, we usually go out of our way to 'separate' our sounds by using capos at differing positions or often one guitarist uses no capo at all - and usually changing capo positions and chord shapes with each song. It's a very effective technique and gives a more varied sound throughout a set for the audience to appreciate.
The capo is simply another useful tool for a singer-songwriter.
Many songbooks now publish two sets of chords so that guitar accompanists can play songs in either the original key or in a key more suitable for the singer.
Since I am self-taught I don't really know where I fit in to discussions of "beginner" or "intermediate" or whatever; I figure playing guitar works best when I maintain a sort of "beginner's mind" about it. Meanwhile, the capo allows me to facilitate song sessions and to get more people singing, so I use it happily and often.
Better question in my mind would be who doesn't use the capo ... I thought pretty much everybody did from time to time.
For instance, can anyone here play "Here Comes the Sun" at the 7th fret without one? Dang that cheatin' George Harrison!
Actually, I don't play barre chords at all, prefering to cover the e string with my thumb. And I'm too old to start learning differently.