Maybe yes, maybe no. It's a business venture, like any other. The proof won't be in the short run, since Apple doesn't do things for the short run.
But let's look at it this way. For those who decide to buy an Apple Watch because of this feature, every one of those Watch sales is a decent chunk of change for Apple. Add to that the monthly subscription revenue... I'm sure Apple's number-crunchers were able to make a compelling argument to invest in the studio and staffing costs.
But yes, even with a compelling series of Keynote presentations and financial analyses, they can be wrong. But for a product and service that is sold to a worldwide clientele, even a relatively "small" population of users can be big enough to float this particular boat. Within the overall universe of Apple products and services, this doesn't seem likely to be a major contributor to the Annual Report, but as long as it does add something positive to the bottom line it's likely to survive.