We currently have two Delta AMEX. The initial rationale was that my husband would get the sign up bonus. Then we kept it because it because it was a "break even" with the flight credit. The only domestic flight we do together is Hawaii, rarely Seattle. I don't think my husband has ever flown without me domestically, except for work, when his miles were retained by his employer. All that to explain, that we don't need for him to get a free bag for domestic travel. If he travels domestically, he would get free checked bags by being with me.
Now that status is only based on dollars spent, we never even get close. It was nice to get the upgrades It does irk me that the $3000 plus, that I spend on airline tickets to get my daughter home from Hawaii twice a year (and her twin sister to Hawaii for spring break) don't count toward my status, and the girls don't fly enough to benefit by the MQD.
We now have a Chase Sapphire Visa and a AAA Visa. We needed to get $5000 in 3 months to get the bonus on the Chase card. So now, that we've done that, we are working on making sure both AMEX cards get the $10,000 for the flight credit. If we weren't redoing our deck, I don't think we'd get there. The cash back benefits of the Costco, Chase and AAA far exceed anything we get with Delta AMEX purchases. And those three cards have other benefits for us, and there is no fee on the AAA and Costco cards.
We did get extremely cheap flights with skymiles to New Zealand and the 15% off added to the savings. I think the answer is to keep one Delta AMEX, to retain the domestic free bags, for the flight credit, and the 15%. We'll use the card to purchase airline tickets and then whatever we need to purchase to earn the flight credit. We'll dump my husband's AMEX and get a joint card for him on my Delta AMEX.
And, there is a reason they are called "sky pesos"