One is allowed, one is straight out banned.
One is high up in the sky, one is on the land.
How is it better for those batteries to malfunction in the passenger compartment instead of the storage compartment of the plane? I don’t understand that.
Cabin crew on aircraft have fireproof bags and rather effective fire extinguishers. Dealing with a battery in the cargo hold isn’t possible.
If you want to carry a battery on an aircraft it generally has to be less than 100 (sometimes 160) watt-hours, whereas e-bike and other batteries are often 10x that.