[ue_]

That's largely a matter of opinion, and you must factor in what counts as a detriment or benefit, which varies with 4chan's goals. Arguably 4chan doesn't really have a goal, though some (particularly the alt-right type people) would say it's a detriment, and people like me or some users of non-political boards think it's a benefit, as one of the large concerns is that /pol/ is infecting other boards, despite the fact that it was made as a containment board.

Others boards such as /mlp/ however do not show such growth into other boards, perhaps because the rule against ponies is stronger than the rule against racism.

[wcummings]

"Containment" boards are pure fantasy, they just give the worst users a place to coordinate their attacks on other boards.