We get a Primal Infusion for maxing renown for each of the faction. By that point though, most gear-oriented players will have already crafted everything at 405 from Primal Focus drops, and will have no use for more Primal Infusions.
I just think it is strange that the reward for hitting max renown is just going to be a vendor trash item for me, and likely a lot of other players. Maybe this could be changed to a Concentrated Primal Infusion, so we can upgrade gear further?
Edit: The opposite situation would be true for players who hyper-grinded the factions early. They were able to craft with the renown Primal Infusions, and now are just collecting Primal Focus with nothing to do with it.