No no flyburg, far from it. The magenta line you generate with an extended centreline is surely the most logical reaction to radar vectors once it is apparent that they will result in an approach as opposed to a return to the STAR.
No way are you a magenta line junkie doing that - as you say it declutters the screen, it is the pressing need for a magenta line to follow at all times and to replicate your anticipated but unpredictable circuit that feeds you duff info on what you aren't actually doing that we are querying. That is making unwarranted assumptions, which was always conveyed to me as bad airmanship.
I use extended centreline whenever I can to clear the screen of ancient data and when on vectors to an approach it is the best tool one has, but it requires a bit of interpretation which is perhaps where the magenta line/instrument junkies begin to get out of their comfort zones and when their crutches like that misleading profile display start to cause disruption.
There is no substitute for situational awareness based on first principles as opposed to relying arbitary magenta lines and computers. The old farts amongst us call it Airmanship.