Latency and Privacy in Lightning

Could someone elaborate on why the self-reported hold times are necessary? Specifically, I’m wondering:

  1. What are the reasons for routing nodes holding onto HTLCs? Is this happening today?
  2. If a routing node is delaying an HTLC, why would they self-report it?

[Edit] To my understanding, if all nodes in a path are honest, this informs the payment sender of the latency at each hop in a route. If a node lies, the difference in reported times by the node and and its peer will localize the delay to those two nodes; in which case, the sender likely avoids both peers.