I usually don't withdraw proposals unless the client has dragged the process on so long that I no longer have the time to do the work but I would like to see an option such as "Client has hired another freelancer" which shouldn't effect our profile or JSS at all. I find it annoying to have a bunch of proposals or active candidacies when half of them have already been hired out.
I understand that some clients may want more than one freelancer (not usually in my line of work) but I may not wish to persue the project if they have already hired some one else. Generally in my case that could present a myriad of problems. I had this situation a while back (not via Upwork) where one developer was doing things and ti generally created a mess.
After a client hires for their project, they have the option of leaving the project open to further hiring. But when the client closes the job, your proposal will automatically go to your Archived proposals and will say that the client hired someone else.
I would like to confirm that being declined in a job, or having open candidacies doesn't affect your profile or your JSS.
I'm aware of the ponts you brought up. I'm just proposing a new option for those of us **bleep** enough to want to keep the proposals page as clean as possible.
I'm not sure if withdrawing a proposal affects the JSS but it seems a lot of things here do.