Risk might not be great enough. They're balancing convenience and safety. IIRC the hoverboards had a higher risk because of how many cheap ones burst into flames and people didn't want to use them in flight so it wouldn't bother them if they didn't have them.
The "hoverboards" have a much bigger battery, with far more stored energy, and are also designed such that they can release that energy more quickly since the application requires it. A typical phone has around 10-15Wh capacity, hoverboards are in the 150-100Wh range, and laptop batteries are usually <100Wh; these are also cells which are designed more for long low-current discharges.
