I would never go inline for punching color jobs. You can buy top-of-the-line equipment for the same price. I run gobs of full color spiral presentations two-up on 11 x 17, and it would make my run costs go through the roof if I had to do 250 qty 150 page presentations only one-up to save some time. Also, If the presentations are ever full bleed, you are boned and need the extra equipment to cut and then punch. I used to have a hard-on for getting the inline punch for our J75, but after realizing I actually run all of my presentations two up, it just would never add up to a cost savings.
But, if you are looking at adding it to a model like a D135 or a Nuvera, you might be right. We don't deal with too much B&W anymore, but it seems to me that running 2 up for B&W booklets or presentations would be counter-intuitive at the fractional click costs.
Also, when your digital press goes bye-bye, you don't have to worry about buying all of the punching equipment again.