See the direction I was taking is how openly easy (literally open) this setting can be used to pretty much show everyone's post from one user to another without any sorts of restraints. Not towards any sorts of malicious attempts or whatever the case may be, but merely taking advantage in a playful manner.
For example, what if someone sends a image to another saying "Hey, I'm gonna show you a picture of a giraffe." then moments later it starts piling up with comments about the giraffe with the individual asking on where they come from...oh of course, from the main page because we can clearly see it all.
Is it anyone's business? probably not, but it's not to say that the user who comments is at fault when it's totally within the open. It's like finding loot, except everyone knows its there now. The standard case is probably to not care about it all...I can agree with that, yet there may be a post where it makes you question as to why they posted it up for everyone to see.
So you, as a moderator, may find it useful since you can clearly catch anyone within the act of any types of post (Such as mine, which I'm sure you removed my posts, I respected it since it is considered spamming.) yet with the previous setting, would it truly be considered spamming if only one post was allowed before? course it would be pointless since no one can see the multiple posts in one shot.