I'd have to say that nearly useless is a complete overstatement. It's helpful for quick browsing from cb chatter, and how often do you see nodes named by Numbers? In fact, It seems that the only ones that would challenge this would be people who name their nodes full numbers which is absolutely ridiculous since it doesn't give a descriptive title, and probably won't get much attention. Just my 2cents
OK, let me qualify that. Nearly useless to me. 90% of my usage of [id://nnn] is to refer to other nodes from nodes I write. Since those are more-or-less permanent entries, I look up the node of interest, and insert its number into my node. Now, I cannot use [nnn] for that, because some person might insert a node titled nnn, and then my article would refer to the wrong place.
So, it's OK for chatter, where you can make corrections if the search takes you to the wrong place, but at the risk of repeating myself, it's nearly useless for people like me.