Point? I dunno, you tell me.
Anyway I think it is worth distinguishing between gas and diesels too. Turbo's seem to be an efficiency penalty on gas engines, while an efficiency boost on diesels.
lower peak bsfc for spark normally aspirated (page 874, fig 15-38)
lower peak bsfc for diesel turbo (page 876, fig 15-40) (plus much better power/weight at improved bsfc)
http://www.rmcet.com/lib/E-Books/Mec...ndamentals.pdf