Most of my family doesn't eat that much meat in general, and half of them don't eat beef. We usually share one big steak at the table. For shared family-style serving, slicing it beforehand makes it easy to serve. If I grill one steak for myself, I'm not pre-slicing it.
And yeah, warm plate or not, by the time I get to eat it, the meat is usually cold.
Lando's post pretty much nailed it.
Sear is a function of heat into the meat. Cast iron preheated on the stove or in oven, you're putting heat into the cast iron and then relying on conduction from cast iron into meat. It is a great material for that use because of high thermal mass (in layman's terms, the metal holds a lot of heat). In a Salamander/Ooni, your heat is the radiant heat from the oven faces. That heat needs to go directly into your steak, not into heating up the pan and then from pan into steak. Unless you preheat your pan, the pan material is doing nothing to sear, it is actually a heat sink taking in heat that should be going into your steak, and the more thermal mass, the more heat the pan is taking in. That's why I recommended thin aluminum if you don't preheat; it is the lowest thermal mass, so it will take the least amount of heat to heat it up. Now, if you DO preheat, a cast iron preheated in Ooni might be the ultimate sear, but be very careful of the underside as it will sear very quickly (and the pan will be hot as f*** when you try to handle it).