The fundamental weakness is that any service facility (whether it's a doctor's waiting room, an auto repair shop, a restaurant, or a help desk) has a limited capacity. As soon as the number of people desiring service exceeds the number of people that can be served, the system starts to break down. Reservations/appointments become essential, patrons who require additional time create delays for all who follow, etc. Cue the velvet ropes and teams of burly bouncers with clipboards. "Sorry, you're not on the list!"
How much space do these WeWork centers have to devote to non-paying clients? Presumably, Samsung will pay rent for a certain amount of space within the WeWork facility. What will Samsung say when that space is full? "You're welcome to rent a desk from WeWork at $X per hour, and we'll call you when we're ready!"
Purely from a business standpoint, a retail shop is far superior to a lounge/rent-a-desk location for a service facility - it's better to have bored, waiting patrons browsing goods worth hundreds to thousands of dollars than to sell them snacks and desk space. Even the cheapest accessories on sale in an electronics shop generate more revenue than snack foods. And if you've setup shop inside someone else's place of business, the opportunity for ancillary sales belongs to your landlord, rather than reaping the rewards of gathering a captive audience.
To me, the elevator pitch at Samsung was, "This is a lot cheaper than setting up our own retail shops." In the end, they'll get what they pay for.