My question - is there any benefit to scanning black and white film over scanning colour film of the same ISO and doing a colour to b&w workflow on the computer? As far as I know the benefit to compromise relationship is as follows:
1) scan only colour: carry around fewer options of film and let silver efex pro provide much more control over tonality (once scanned) than a single coloured filter in front of the lens ever could.
B&W film has a far greater dynamic range than color film. If you want a b&w print, b&w film is far superior. Further, you don't need silver efex, or any other plugin, you need to learn how to use curves...
2) scan b&w film: the film has a finer grain at respective ISOs than colour because the light sensitive chemicals only respond to light levels and are not separated into colours (this is a complete guess - please correct me).
Color is dye-based and not grain based. Therefore less grain, generally speaking, of course. However, hard to beat Ilford Delta in Xtol... especially with all that extra sensitivity.
Museum Quality Drum Scanning and Printing