Nothing wrong with hawking cards for SUBs - in the past year I got new UA and DL biz cards solely for that reason (of course you have to consider the reduced value of SUB miles due to devaluation). They immediately go into the sock drawer after initial spend is completed, and renewal will depend on retention bonuses and how much I value the pitiful perks (e.g. 15% discount on skypesos redemption).

But - as bears repeating - nobody should be putting any discretionary or everyday spend on an airline card unless you are accumulating EQP for elite status. And even then kind of questionable given the paltry elite benefits.