I wouldn't describe a result that eliminated the species conducting the experiment in the majority of world-branches as "successful", although I suppose the use of LHCs could be seen as an effective use of quantum suicide (two species which want the same resources meet, flip a coin loser kills themselves- might have problems with enforcement) if every species invariably experiments with them before leaving their home planet.

On the post as a whole: I was going to say that since humans in real life don't use the anthropic principle in decision theory, that seems to indicate that applying it isn't optimal (if your goal is to maximize the number of world-branches with good outcomes), but realized that humans are able to observe other humans and what sort of things tend to kill them, along with hearing about those things from other humans when we grow up, so we're almost never having close calls with death frequently enough to need to apply the anthropic principle. If a human were exploring an unknown environment with unknown dangers by themselves, and tried to consider the anthropic principle... that would be pretty terrifying.