Wot I mean is, if I'm just wanting an ILS for practice on the way back from somewhere, and it doesn't matter very much whether I do it or not, I don't want to get in the way of some else whose main purpose of the flight is using the ILS, say instrument training or test, or a test flight, or a commercial flight whose SOPs require them to use the ILS, or whatever.
So I will negotiate with ATC that I'll take an ILS if it's not going to hold anyone else up, otherwise I'll join visually. And I'll certainly junk the ILS and join visually if the alternative is holding!