Arguably, a very small single driver making all the sound (headphones) and without a room to colour the sound is more accurate by default then a speaker with many drivers, a XO,, the crossover components, the room, the off axis response, ect.
However, the sound pressure that speakers do in a room, the soundstage being put in front of you with a real phantom center, feeling the bass with your body, ect is just two different experience and cannot be replicated with software + headphones.
Well the first phrase holds true for only some loudspeakers, but not all!
Besides that I agree.
From my point of view, it depends very much on what kind of music you are listening to.
Classical music recorded in a concert hall, with only a couple of microphones, does not do it for me on headphones as some of the experience in listening is the sense of having the orchestra in front of you and recreating the acoustic of the concert hall. One can argue, that only a multi channel setup can do that.I have heard binaural recordings over headphones that comes some of the way, but for orchestral works only loudspeakers work for me. Quite another story is music made in a studio. Here the experience from listening through headphones can be very exciting althoug quite different from loudspeakers.