I am describing its original purpose in the sense of prayer's original purpose in psychology and sociology.
One can learn lessons from religious practices without becoming religious in the process.
Besides prayer in general, take another look at the step:
... improve our conscious contact with God as we understood Him, praying only for knowledge of His will for us and the power to carry that out.
Do you know what that is? Look at it as an athiest, and imagine what purpose that step serves.
Seeking to understood God and his will? That's not - as many would put it - a human trying to communicate with a Sky Dad.
That's a human trying to understand his own Coherent Extrapolated Volition: "our wish if we knew more, thought faster, were more the people we wished we were, had grown up farther together; where the extrapolation converges rather than diverges, where our wishes cohere rather than interfere; extrapolated as we wish that extrapolated, interpreted as we wish that interpreted"
https://en.m.wikipedia.org/wiki/Friendly_artificial_intelligence
When a human makes a gesture and a sound on cue, they're usually engaging in in-group signalling. But when a human prays and meditates on finding God's Will for them, they are trying to imagine their own desires and needs from the standpoint of a superior being. One with more information, a greater mind, a greater moral compass. They are trying to make themselves better by imagining the ways they could be better.
Athiests do this too, they just call it cognitive behavioral therapy and moral philosophy.
It sounds like they don't want to take responsibility for that user choice or be connected to anything that happens because of that choice.
It would still be an insecure choice, even with obvious UX distinctions. It would only be a matter of time before headlines muddy the waters with "intercepted Signal messages reveal..." or "Judge rules in favor of subpeona for unencrypted Signal messages..."