I don't think it gives you nothing. As an example, say a 0/1-day gets dropped and someone starts compromising systems. You're trying to get round your estate e

I don't think it gives you nothing. As an example, say a 0/1-day gets dropped and someone starts compromising systems. You're trying to get round your estate ensuring patches are in place, but that takes time. The bots are starting with the low hanging fruit, systems on default ports. Being not on a default port helps, by buying you more time to react.