Though one thing that differentiates them is that the systems we learnt about titles and dates being typically interactable had mouse pointers. I can't quite express why, but it feels less annoying to mouse over something and discover it's interactable (via a change in the mouse cursor) than to stab at text on the screen.
I guess one is a more passive "will this do something if I interact with it" while the other is a more proactive "I'll try to interact with this and see if it works". One results in a yes or no answer, while the other results in a failed action, which seems more frustrating to me.
That all just goes to show that, as you said, it's more complex than simply missing affordances = unusable UI.
Though one thing that differentiates them is that the systems we learnt about titles and dates being typically interactable had mouse pointers. I can't quite express why, but it feels less annoying to mouse over something and discover it's interactable (via a change in the mouse cursor) than to stab at text on the screen.
I guess one is a more passive "will this do something if I interact with it" while the other is a more proactive "I'll try to interact with this and see if it works". One results in a yes or no answer, while the other results in a failed action, which seems more frustrating to me.
That all just goes to show that, as you said, it's more complex than simply missing affordances = unusable UI.