I use that feature a bunch when it comes to automating browser actions with Selenium / Chrome web driver. That selector tool makes life so much easier when it comes to making sure you get the right element.
I see how that can be helpful. However, in practice, it gets tricky. For example, The node can have N inputs, and the property that holds the data you want can be in any part of the inputs. We would have to add extra fields to the nodes where the user can define where to look for the data to create the data that feeds the select (the field you want to populate with options). That, not sure if it will make n8n more difficult rather than easier to do. That is my opinion thinking about it for 3 minutes, with some more thinking I might change my mind. Btw I think @david had something like this in his mind.