LTS, I agree. Many singers who accompany themselves on guitar tend to be better guitar players than singers, or else they put more into the guitar accompaniment than their singing. The understanding of the words often suffer. The accompaniment to a song should be understated so as to emphasize the song.

I am a fiddle player who can also sing, but can't do both at the same time. So I play a fiddle intro, sing unaccompanied, more fiddle between verses or as a break, etc. I enjoy this because I get to do both instrumentals and singing. And the singing comes across better, as I can concentrate fully on that at the time, and I think it focuses people's attention on the words and message of the song. It also adds variety for the listener, to both play an instrument and sing, but not at the same time.

Cheers, S. in Seattle