We tested it on a Google Pixel ourselves and found that, while the AR Stickers and Motion Photos didn't work, Face Retouching and the exposure lock were functional. Anyway, this is a really handy trick, as it narrows the differences of what you can do with Google Assistant on different devices. As such, I recommend you take all caution when deciding whether or not this piece of software is meant for your device - or if you're going to risk it all to run with the newest in new. If you tried to do the same with Assistant on the phone though, you were greeted with an error message.
Google's digital assistant has always been able to control a Chromecast, but only from a Google Home speaker. We have seen many apps making their way to the Play store in the past like the Dialer, Google Keyboard (now Gboard), Google Assistant and more. Google is one step closer to achieving that now. The latter can also be turned off as of the Google Camera version 5.1, whereas the volume key feature may end up moving again depending on user feedback seeing how not everyone will think of the functionality as a "gesture". But with 30 seconds of work and an Android phone, you can pretend like you've got Google's newest flagship, thanks to the release of the Pixel 2 default launcher.
For now, it appears only Google's devices support the feature, but Google says it is working with carrier partners and Android OEMs to bring the integrated video experience to more devices in future.