A lot of it just seems to be marketing. Present the shiny new toy, get the news headlines, people book their stays, and then it doesn't really matter if they ever actually make it into the parks.
Eh, maybe. I have a less myopic view... I think their Imagineers just like pushing the envelope, and there's a difference between awesome tech vs things that can withstand the wear-and-tear of millions of guests.
Nothing about all that tech makes me think Olaf could withstand a hug from an excited kid.
Disney does a ton of R&D that doesn't directly make it into the parks, such as smokeless fireworks (they donated the patent for this) and their holotile floor (basically an endless VR room you can walk around). I imagine they don't know the practicality at the start, like any good R&D.
Amazon drone delivery comes to mind…
We're probably looking at a halo effect ?
Similar to concept car demoed at trade shows, we get an idea of Disney's technical engagement, and some of it will perhaps in some way or form get applied into future products/attractions.