Real world case where I've observed these load characteristics: A cluster of three Redis nodes, one of which is primary and therefore has slightly (but persistently) worse latency. Pick-2 would send significantly less read traffic to that node. Like you say, it's no worse than a 2x difference, but I'd prefer better balancing than that.

(Pick-2 also can at most give 2x less traffic to a node with terrible performance, which is not awesome.)