Cactus and Diablo I / II were exclusively made for Windows (even though I use FreeBSD as my primary OS, and used to be a Gentoo Linux developer). Thus I wanted full and seamless integration with the OS that the game was originally made for. Since Diablo II can run on UNIX-like systems through Wine (fairly well - at least for the Vanilla game, not too sure how mods would interact given specific uses of OS behavior, hard to say without actually testing every single mod made), and also because all of the Cactus platforms are self contained and independent (even independent from Cactus itself), it would be easy for someone to implement a Cactus like type of system on UNIX-like systems. You would just need to do the same file switching that Cactus does, and update the "registry" which would actually be located in a WINEPREFIX. I will leave that exercise for someone else since I'm just interested in maintaining Cactus on Windows 7 and Windows 10 exclusively.