It wasn’t just lack of demand. It was that versus the actual cost of increased failure rates due to introducing multiple additional points of failure to every battery.
PowerCharge had significantly higher rates of self-discharge and potassium hydroxide seepage. They were more vulnerable to corrosion in suboptimal storage conditions, perhaps due to putting conductive film beneath the insulator wrapping.
In other words the proposed value-add of that product line (convenience) was also directly impacting their core brand (maximal reliability).