Some reasons.

1. Apple needs new products - even something like this gives headlines, reminds people about the cool product, so maybe they choose a different one. Even if it doesn’t make money it keeps Apple as “new and innovative” and helps recruitment.
2. Gets it out there for developers to try out, come up with use cases and killer apps.
3. People (prosumers) come up with uses that Apple and Devs may not have thought of.
4. Allows people from #4 to bring them to work - after all, that’s how Apple got big in the first place… People bringing their Apple ][ & visicalc, since their IT wasn’t responsive enough or people hated working on mainframes. It wouldn’t surprise me if one of the doctors brought it in himself thinking it might be useful.
5. Allows Apple to come up with justification for the R&D money for the GUI, UX, hand gestures, etc that they’re going to need later. Gotta keep shareholders happy.