In today’s day and age with no change fees (BE exceptions) more and more shrewd travelers are going to book the same flights on multiple airlines (not BE) with points or money to cover themselves.

As long as you follow the rules and cancel 2 hours before takeoff there is zero downside as long as you can use the airline credit within a year. DL Skymiles go right back now at zero cost for everyone now (used to be only PM/DM).

It is so prohibitively unfair to book a flight 6 months in advance for $250 and then get a full refund due to cancellation but then have to pay $1,000 full fare for the same flight on the day of travel on a different airline. And at Christmas multiply that difference by 2-4 additional family members.