Note for the non-americans who use significantly better measuring systems.
Awg = american wire gauge, I.e wire diameter.
18awg = 1mm diameter
16 = 1.3mm
14 = 1.6mm
12 = 2.1mm
Yes smaller numbers are thicker wires.
Besides the electrocution hazard, another problem (in the US) is that someone allowed non fused 16 and 18 gauge extension cables on the market. We should only have 14 and 12 (or start putting fuses on the cords like some other countries)
14 should be for “light duty” like electronics or lamps. What you don’t tell people is that pretty much anything inside the house will run fine on 14awg wire.
12 for everything “heavy duty”.
The idea is people use the same wire that matches what their breakers are rated for. A 20amp breaker doesn’t know that the 100ft 18 gauge extension cord feeding 3 surge protectors with every kitchen device and the “diy powered garage” is going to melt long before 20amps.
Is it overkill? yes. If you draw too much current will the wire overheat and burn down your house? Not if the breaker trips first.