Hue Essentials supports watches with Wear OS.
The Samsung Galaxy Watch4 and newer watches are supported. See for more information: Where can I download Hue Essentials for Wear OS?
Older Samsung watches (like the Galaxy Watch3) do not run Wear OS but Tizen OS. Hue Essentials does not support Tizen OS. Hue Essentials will not be available for Tizen OS which is only used on old watches.
In future is a long time… Since you’ve given me that same answer for about 3 years ago! 
Although the HueEssentials team is working hard with quiet some fantastic features (!), I would love to have this available for the Samsung Watch too 
There are a lot of crappy apps for Samsung watch, so you guys would really be a differentiator!
Google and Samsung will merge their Wear OS and Tizen-based smartwatch OS. This means new Samsung watches will be supported by Hue Essentials.
Samsung will not update existing Galaxy Watches with Tizen as it seems. Galaxy Watch 4 will be the first upcoming watch to run Wear OS / One UI.
Hue Essentials will receive updates to target this new watch. As it looks for now, the Tizen OS of older Samsung watches is a dead fish in the water.
Although Samsung still supports those older watches during some years, it would not be wise to build a Hue Essentials release for an OS which is available exclusively on a retired system. Building a version for those watches is time-consuming and hardly worth the effort considering Samsung’s decision.
There is currently a new version of the Wear app in beta which has UI improvements for the Samsung Galaxy Watch4. Let us know your feedback! Join the beta - Try new features before they are officially released