but there is no need to faff at all, with or without a warming drawer (which I've never heard of). When I cook for visitor people at home there is usually a voice that exclaims "warm plates!" which is nice.
You may or may not faff and waste time but some people certainly do e.g. my father and OP's MIL and it can be quite irritating. Regardless, people who don't warm their plates just don't like their food to be piping hot. It's not because they are inefficient and need tips on how to do it.