In this case, I simply didn't remember that I already had a Stream Link on one service when it became available on another. Interestingly, I checked now and apparently it left Hulu and got added to Netflix, so the advantage would be I could try one and then the other in case something like this happened. The problem with Stream Links vs. JustWatch/Realgood is managing things leaving services. (hint, hint, wink, wink Devs).
Another situation I have is a recording and a Netflix or a Disney+ Stream Link. It might just be a preference of which device I'm streaming on or where I am in a future world (home vs. out). Or again, if one leaves another. It really is coming down to management. I would like to not have to search my collection to see if I already have it when I add something.
For instance, there are a ton of movies that are on both Kanopy and Hoopla. I prefer Kanopy from a UI perspective and because I have more items I can take out per month. So I keep a folder off to the side with the Hoopla links that are available elsewhere, but if those programs leave those services I'll have to move the Hoopla links back in (assuming they are available). I'd really prefer to just set and forget, and if I happen to try to launch it and it doesn't exist deal with it that way.