I’m reminded of our common denominator every time I travel. I’ve been in a minyan where the 7th thru 10th person only daven once in a while, I’ve asked people who I know not to be frum, if they’ll stand in as the 10th.
Hard to judge what the value of a yehei shemei rabbah and omain is from “once-in-a-while” people, but I’ll bet its way up there.