The mystical and religions / believes can very much increase the depth of a world and all the best stories do have something to say on that topic. So it make sense to also think about it.
As for the lay of the land I don't define "the truth" about which gods, devils and other entities exist. Rather I want to compile a list of beliefs/religions that can be used for your own version of Pangaea.
And whether the entities those beliefs worship really do exist - or even if they exist: whether they care for those puny little creatures? That I also leave up to you.
The details of each religion/mythology are described per species in the R chapters.
Belief has, in reality, a huge impact on your day to day live and on the culture. It influences what traits and behaviors we value and which we condemn. It effects on how we treat other people. It can even be a huge part of what drives us in our life.
Cutting this out of an RPG will make it shallower.
Look at earths history. 'nuff said.
Temples can be used as places for healing. And not necessarily in the sense of "make a sacrifize, pray and hope", but with real healing abilities: A priest/ess of the temple might have the skills necessary to provide healing. The healing itself will then not be done by any PC but by the priest/ess NPC.
The temple itself can give a great surrounding for creating advantages to increase the chances for this healing:
Donate money/items (Create an Advantage using Resources)
Help out others in need (Create an Advantage using Physique, Lore or Crafts)
Meditate to find inner peace / pray to an entity (Create an Advantage using Will)
Of course some small payment (or maybe call it "not-as-voluntary donation") might be asked for. (@GM: Overcome with Resources.)
Of course whether you want this or not is up to you. But for divine interventions you need something "divine" to exist.