Shower Waterproofing

Hey fellows tile guys , I'm wondering if anyone here has tried the liquid hydroban membrane over Gypsum wallboard , their data sheet says it is a suitable substrate just wondering because I can't recall ever having seen someone do that , I have tub shower that I started prepping a while back since I had in between time and I was counting on doing kerdi membrane hence the Gypsum wallboard, but I really Would like to try the laticrete liquid hydroban. Let me know if you have any input.