Perhaps he is “observant” in the way Chuck Schumer is an observant Jewish man.
He observes actual Jewish people practice Judaism.
He doesn’t practice it, himself, mind you. He just observes it.
Over there — somewhere FAR over there.
Good comparison. Biden is "culturally" Catholic. He was raised Catholic, doesn't believe in any of the "malarky" it actually teaches, but he DOES like to do photo-ops at Catholic gatherings and attend Catholic holy days where he can do awkwardly long hugs. He probably collects "Catholic" stuff like rosaries, too.
I think Kamala Harris's "Baptist" faith is very similar as well. She is more than happy to show up at black churches and rally the troops. But believe in anything the religion actually teaches? Nahhhhhhhhh....