I would say Gibbs is a rarer talent than Bijan. We almost never see receiving backs come into the league as polished as he is, and none of them have had 4.36 speed. It isn't a perfect comp, but Christian McCaffrey is probably the last guy like him.
Bijan is a hyper-athletic power back. He isn't a bad receiver, but he isn't the elite receiver he's billed as IMO, and most of his value comes as a pure runner.
Super-athletic, super-productive pure runners come into the draft almost every year. Last year had two guys like him in Breece Hall and Ken Walker. Travis Etienne was kind of in that mold in 2021, and Jonathan Taylor was definitely that dude in 2020.
So I could definitely see a team justifying a pick of Gibbs over Bijan, because Gibbs offers a skill set that you may not see for another 2 or 3 years.
But the thing with Gibbs is that you have to be willing to scheme for him as a receiver, and throw a ton of passes to your RB. Not every offense does that. But OTOH, every offense in the league power-runs quite a bit. So Gibbs needs to find a team with the right fit. Bijan is pretty much foolproof from a schematic standpoint.