I think you always need merits, even if it's legendary.
The merits are the recognition that what the person says/does is useful for the readers of this community, whether that person is legendary or not.
Daniel91 is OP of our merit giveaway thread where members can submit their good undermerited/unmerited posts and that thread has been pretty inactive for quite some time. I think that in the last six months or so we had maybe 5-6 submissions and that's what he (probably) meant when he said that no one needs/wants merit anymore in our local board anymore.