This is somewhere on my list, although two things are important to mention here:
1. I'd prefer to wait for official support for multiple rooms, to be treated as a single playarea. Although I haven't tried just walking around my house when drawing the guardian. So it might be actually already working. I'll try that.
2. There are lots of other things that are required to make Tea For God a game and I want to focus on that. I have a wish list, things I'd love to add, I really want to add, but that may wait for post release. One of them is the support for multiple rooms. Second is multiplayer.
But in general, I admit you're right. Having support for multiple rooms would add a lot to the game. For sure I will be experimenting with that.