Clock Radios with Lithium Batteries

Why don't you google that?

No, no concern. The difference is the size and power demand. High output batteries can generate a lot of heat when discharging high currents. E-bikes have large batteries that can discharge and charge at very high rates. The combination of a large battery with poor heat removal and the high currents can result in very high temperatures which can lead to a fire. The small battery a clock radio will never be asked to discharge at a high rate and because it is small, it has much better heat transfer so it can stay cool.