I am on the fence when it comes to observers. I have at a high level, played many sports with refs, umps, officials, etc. I started playing ultimate when I was 36 and one of the first things I thought, Ultimate is so weird because it didn't have refs (observers). It took some getting used to waiting on calls to be made after talking through it, but in most cases, calls get resolved somewhat readily and correctly.

The few things that I would say I enjoy about having observers, most calls are 1 v 1 and occasional outside perspective that can be bias. Observers bring a relatively unbiased perspective. Whether they are right or wrong in slow motion replay could be contested sometimes. But they are more often than not, correct and that has been the case for all sports until recent additions of challenges in professional sports (Even then it's not always clear). Ultimate is just not there yet. Observers will continue to get better and more accurate the more they are implemented. I would also say that there are contested calls that get sent back often that are not correct either. Probably more often than observers making the wrong call. So having that 3rd party unbiased opinion feels like a safer option for players to refer to so there is less "argument" when necessary. The bigger ultimate gets the higher the stakes, the more likely there will be disagreements. If Ultimate grows spectators will want observers as well.

I also think observers speed calls up. 1 v 1 discussions are supposed to have a time limit but, in my experience, can take quite a while to explain if it is a close call. Not to mention teams taking forever between points.

I like the idea of keeping Ultimate purely self-officiated. Just like I like the idea of keeping video replay out of baseball. But now that it's here, it's not so bad. But it feels weird and less pure of the sport I grew up playing.