If your bags missed your flight due to weather related weight and balance issues, you’d expect the airline to deliver them to you when they finally arrive. If your flight was diverted to LGA from JFK, but your bags arrived to LGA instead, you’d expect them to be delivered. If you were on a 9-Hour delayed flight due to WX in a connecting city, but were able to arrive earlier to the destination by taking different flights, but your bags stayed on the original routing, you’d expect them to be delivered. This is no different.

The airport change is a red herring that confuses the issue because it brings up images of voluntary SDC. That’s irrelevant, though. In this situation, OP simply chose the most rational way to get to their destination as quickly as possible when their original flights were affected. What matters is that WX related IROPS caused the bags to not be delivered on time to baggage claim, and Delta should have taken responsibility for getting them to OP.

OP, I’ve found that the phone agents are pretty useless for baggage issues - they are completely unempowered and have to rely on local baggage offices for assistance. Your best (possibly only) bet is to find an advocate at your destination airport.

The OP’s real problem is that the airport used standby as a tool to get him on a flight, and that’s causing the business processes for baggage to think his change was voluntary. An e-mail to Customer Care should result in easy compensation, I’d suspect.