You guys might both be right, I'm not sure. On the Marlins, I just get the sense that part of why Bendix was brought in was to make them a sustainable winner. If they are trying to compete next year, then they should look at extending Jazz and an offseason where they can supplement the guys they do have with something else.
Their division is also really tough, with none of the other teams set to be on a downward trajectory for at least a few more seasons. With how their prospect group is congregated, I just expect them to start collective talent. Assuming Luzardo and Alcantara come back healthy, they will be able to trade them next year for even more young talent. That said, they could still prefer closer to MLB ready talent for a variety of reasons.
With Davis, I get the reservations, but I think there will be caution about trading the guy you took 1.1 because he hasn't had the smoothest path to the majors. I'm neutral on it, because I think Jazz gives you plenty of certainty at a position of need to make it worth it in the meantime, even if Davis turns things around eventually.
I expect a big part of it comes down to what else is on the table. The Mariners are arguably more desperate than us and also have a better group of prospects to trade from. They are in a dog fight and probably need to win the division to make the playoffs. It's too hard to speculate without know much more specifics, but if their sights are set on Jazz, it's possible that his value gets driven up.