Fairly recently I saw a custom shirt that was 100% sewn by hand. When I say 100% sewn by hand, I mean that literally every single stitch, from both rows of stitching on each side seam, to the bottom hem, to the buttonholes, to the collar topstitching was sewn by a man with a needle and thread. The stitching was so fine and so "regular" that I had to look twice before I realized that it was in fact done by hand. In no part of the operation was a sewing machine involved. It also took 3 days to sew this shirt, which is
cost-prohibitive both for the maker and most potential clients, so he also offers less expensive custom shirts which he uses sewing machines to assemble. This shirt cost quite a bit more than Kiton shirts cost. The work was beautiful. The quality of the hand-stitching made Kiton, Borrelli et al look positively crude. The button-down collar had a roll that no Brooks Brothers button-down collar has probably ever had. I was able to appreciate this shirt from an artisanal standpoint. Nonetheless with the exception of button attachment(issue of accuracy) and the possible exception of buttonholes I prefer machine stitches.
If the maker has a very good buttonhole machine then I see no problem with machine-sewn buttonholes. Some of the older Troy Shirt Makers Guild shirts have beautiful (machine-made) buttonholes.