Personally, I am much more comfortable singing with a guitar in front of me. I bet there are others who feel the same way. Do producers cringe when they hear that? Is the normal strategy to record a scratch track with the intention of recording cleaner parts so mixing will be easier? I would love to see some techniques in production strategy, mic setup and mixing.
This is a marvellous question! I apologise for not seeing it earlier! Yes, I have done that many times. For instance I was interviewing Bradley Cook today about The Counting Crows song 'Last December', he told me that was take two, the whole band tracked live with Adam sitting at the Piano playing and singing! If the vocal is amazing then I say go for it use it and keep on tracking!