What are the pros & cons?

In my opinion that could be entirely subjective to each person based on their preferences.

- Those of us that flag content against the community guidelines will almost certainly have it on so we see patterns of what the site is being flooded with. The bots appear to go in cycles based on the time of day or origin timezone.

- Enabling showdead provides a chance to vouch submissions or comments that deserve a second chance.

- Those that do not want to see all the garbage and prefer a cleaner site will most likely benefit from having it off.

There are a myriad of other reasons to go either way with it.