Religious belief, as I see it, is harmful by definition. It never works for anyone as well as a reality-based worldview would.
This is a direct challenge to the my thesis, of course. A complete response would have to take on the task of pinning down the definition of a "reality based world-view" and then showing why I think religious belief can be a part of it.
Assuming you mean something like the naturalism described over at godless geeks:
There is an external world that exists independently of our minds.
There are quantifiable natural laws that describe how things happen in this world, and we can attempt to understand them.
These natural laws won’t change when we’re not looking; the universe isn’t totally chaotic.
I'd say that of course, any time you can get sufficient evidence to reach a positive result from these rules, you should use the result. I think there are three kinds of limits, though:
1. IMHO there are some inherent limits in how far this game will take you, but I'm still hoping someone with a real background in philosophy will undertake to answer that question.
2. As a matter of fact, we haven't reached a result on lots of important questions (consciousness, time, existence? Sure, but also humble problems like dividing a cake equally).
3. As individuals, we don't have the time or resources to reason from first principles or even evaluate all the relevant results the species has accumulated before making a decision.
A reality-based world view has to take into account the fact that there are, in fact, significant gaps where naturalism is not useful. I'll undertake to explain why I'm don't think I'm suggesting we fill those gaps with random crazy at a later date.