The way I see it, to believe is not just to "count" something as being real without proof, but to "claim" it as being real without proof. I don't think there's necessarily anything inherently dangerous or unhealthy about counting something as true before knowing for sure as long as it is done in full view and full acknowledgment of the fact that it is not really known for sure, and as long as it does not get pushed over into a "claim". 

An example might be when someone in the jungle decides to count it as being true that there is a hungry lion lurking around every bush and so they decide to carry their gun at all times so as to be prepared for any possibility. I personally would still say that the same thing could be done without the "counting it true" part. It is possible to just walk on in full awareness of the fact that they just really don't know whether or not there are any hungry lions behind any of the bushes and still maintain a posture of being prepared for any possibility and still carry their gun at all times because of the fact that there just may indeed be one out there ready to pounce. 

I don't have to make the intellectual choice to count some unknown thing as being real just to be prepared incase it is. Instead I walk on with preparedness for whatever actually is real. If the possibilities are there, I would still carry the same gun, but not with the mindset that they are out there for sure, but with the one that says, "They might be...so be prepared". I will still be just as prepared, but I will be doing so while remaining totally open, honest and real and still be able to maintain complete intellectual integrity (i.e. not trying to force my mind to count something as real which it can't possibly verify as being such).