Do folks think its worth it to keep/sign-up the Delta Amex Gold just for Takeoff 15 ($99 AF) if one keeps it as a drawer card and has no need for checked bag?

I suppose one would have to redeem at least one award ticket each year and ensure that the 15% miles savings exceeds $99?

I have a DL Amex Plat. now and I'm trying to decide if I should cancel it or downgrade to DL Gold (or cancel and sign-up for Gold for the sign-on bonus)