It doesn't benefit you.
Theoretically, the ability to scale from prototype to production in hours or days is great for rapidly responding to a changing market and demands. If new guns dropped every single day and they all needed holsters this would be great for you the consumer...IF...Bespoke holster makers did not exist. But they do exist, in plethora. And they make better quality products at lower prices.
This structure is not a benefit to civilian consumers. Actually, seeing the ad copy and what RCS is saying has made it clear to me what this is...it's a sales pitch for agency level contracts. You need to be able to show rapid production capabilities and ability to flexibly pivot as a vendor on DoD and especially DARPA contracts. And additive manufacturing gives you that flexibility.
It doesn't appeal to consumers in many respects - because you're able to acquire bespoke products at good prices and usually decent time line. You also have the luxury to wait. But someone who needs 20,000 units NEXT WEEK can't call Milt Sparks.
Which means for this product to succeed on the civilian market - there needs to be a compelling argument as to its superiority to pre-existing products to include bespoke holsters. Perhaps RCS is revealing those strengths in their private social interaction page. I wouldn't know, because I'm not paying for membership to the RCS social club.