I wouldn't have picked up the option, to me he's that replaceable. I think the Panthers are taking a more cautious strategy, not ready to move on yet but also holding off on committing to him until the last possible time.
Basically, he's a competent NFL QB. He's bottom third in the league. That's actually not a terrible thing. You can win some with a bottom third QB. If over time he takes a few steps forward he might be a median level QB. I think those are the kinds of steps that Canales is talking about.
If you've truly got a median level QB, it's probably worth keeping him as opposed to roll on the dice in the draft. But just to be super clear, I don't think he is capable of taking those steps, and I think we should and will move on after the season