I think the idea was that he could be invoked by his name, but they couldn’t have people going around saying “Jehova” (or whatever) randomly without any cool powers happening, so they made up the rule to discourage people poking holes in their flimsy story.
I can’t click those right now, but very much look forward to them. Have one of my favorites:
https://youtu.be/_N66Hud_Tq4