I personally feel the "purely outcompete" idea is BS.In the experiment they ran it seemed like they had no CUC in the "display", so it was just "lighting both display and refugium with light, doing this with several different lights, and seeing which one grew more nuisance algae in the display". So, determining if a refugium could out-compete nuisance algae/prevent it from taking root.
The "dosing hair algae/etc" into the tank is another part of why I'm likely going to shy away from the scrubber. Cool idea, love it, but more maintenance + more moving parts when I'm trying to keep everything simple.
My ATS outcompetes algae in the main tank because there is a big cleanup crew of snails and tangs.
But once you have a CUC (and why would you not) problem solved.
The reason I feel this way is because of observations during tank crashes.
When all my snails die, I get hair algae in the main tank.
ATS running the same the whole time.