It does, sometimes. That is the whole point. Sometimes.
I am fairly new to viewports (and they are amazing) but I was doing some 2D compass that had to infinitely scroll within a UI component indicating sectors like west3 or east4 etc and I had never done something like that. So I asked AI what would be a good approach and it said in 100% confidence that the best way was to use another viewport and to do the group chunked indicator ticks and labels I had expected and suggested, you know, so the last as it goes off screen becomes the first etc. I spent an entire day on it when I realised I could just use the ‘clip contents’ on a normal control node.
Anyway I asked AI if it would not be simpler to just do that and it said, ‘absolutely, that would be much simpler and is a normal approach to this in Godot.’.
Now thinking back, it probably suggested a viewport in the first place because I had been asking about viewports previously. But that was the wrong answer and a bad suggestion that, because I did not know, wasted hours for me. And also I felt stupid because I know you cannot take at face value what it suggests! And I fell for it anyway!
Yes it often helps. But also yes, it often does not help! That is why it is a dangerous tool for learning. Remind me of the format for this or that, fine. Take a look at this and what do you think, fine. For stuff you know, you know when it is telling you nonsense. If you do not know it in the first place, it is a dangerous guide that in the longer term, will waste more time than it saves.
As @athousandships said and others have constantly said here: