+1-ing this as well! I've been using Substance Designer for our pixel art and this tool seems like a much better fit. Cannot overstate how significant OSX support would be for our team's workflow.
I purchased under the guise that there was a supported macOS version ('A downloadable tool for Windows and macOS'), so a working Mac release in the future would be greatly appreciated
+1 on this as I'm on macOS and had bought it based on it being available for mac and windows, but the only available mac release appears to be months behind the windows version.