Most of the new equipment we build has automated grease dispensing systems, where my PLC dispenses a fixed amount of grease through hard-plumbed tubing onto ball screw nuts, linear rail trucks, bushings, slides, or whatever else the machine requires. Those don't need GreaseBoss fittings, but perhaps chould be able to tie into your cloud if they've got some of your equipment and some of mine.
A lot of robotic equipment and repurposed older equipment, however, plus some new equipment with hard-to-plumb areas, has automatic greasing distance counters that pop up a warning/fault on the HMI that reads something to the effect of "Grease Warning: 20km travel on Z axis ballscrew, follow the greasing procedure and enter maintenance password to dismiss or OK to continue".
Those, I suppose, could benefit from GreaseBoss in three ways: First, you could guarantee that the procedure was actually followed (that both the easy-to-access top nut and the buried bottom nut were greased). Second, you skip the maintenance password step by detecting the grease being applied. Third, you could dismiss/reset the warning automatically if my PLC could query your API to determine when the zerks on my machine were last greased.
However, Haas is a machine builder, not a viable business model. A subscription to use the equipment is not going to fly with most of my customers. They're not stingy, CapEx is already huge and grease zerks are cheap compared to the engineering costs they're paying - you're putting in a $2.5M piece of equipment, they don't care if the optional RFID grease zerks are $0.25 or $2.50 or $250 - but OpEx and equipment lifetime are critical. The idea that their equipment stops working because someone in the front office didn't pay a third party is anathema to them. They'd rather spend $250 per zerk once than $2.50 for the tag plus a yearly fee of $5/zerk for the 10-year lifetime of the equipment.