Don’t be afraid of the theological content. It’s a good prayer. God believes in you even if you don’t believe in him.
Just because it is not necessary for you does not permit you to project your opinions on the rest of humanity.
You get value out of peace and serenity, yes? So do I. I take you at your word that you believe in a particular god, I would assume you take me at my word that I don’t believe in any gods.
If both of those things are true, then gods are not required to take value out of the idea of serenity. The only way that this could not be true as if one of us are lying.