But lots of features are likely to be unavailable to invitees (indeed the article specifically mentions a couple) without Apple devices. Apple loves to use network effects to make people with Android phones feel like outsiders.
Also, Apple should not be in the business of making social apps. Hardware and OS is plenty lock-in aka fiefdoms as it is.
I have some sympathy for Apple here; they are selling a premium walled garden, and nearly all popular social apps do one or more things that are rather antithetical to their brand.