you have to look for the most distinctive redletter moment that stamps a flag in those moments of history. What happened then and there that never happened before or after?
1. Seven and Chakotay hooked up. saving the ship before they hooked up wouldn't save their marriage. Seven's standing virginity might also have been criteria to Admiral Janeway arriving when she did.
2. Chell was about to take over the Neelix's kitchen. A Bolians tongue has a cartilaginous lining and their digestive system greatly differs from a human being, making them capable of eating foods that would make 'normal' species' sick or dead. It's possible that those 20 people not as yet dead crewmen Janeway was referring to, all died from Chell's cooking.
3. Miral Paris was heavily involved in the planning of this mission in the future. It might have been a condition of helping the Adnmiral that her local of birth was changed form the DQ to the AQ.
Any other reason is complete shine.