If volts were there only limitation on the design that would be correct, however amps are also important in this case. A 240V UK wall socket can be up to 13 amp

If volts were there only limitation on the design that would be correct, however amps are also important in this case. A 240V UK wall socket can be up to 13 amps whilst a US 110V line is 12 amps. With power (watts) being volts * amps that gives the power of 3120 Vs 1320 watts for UK Vs USA respectively. This means a UK kettle can dump heat into the water up to 2.4 times faster so should boil in less than half the time. Kettles are at the high end of power consumption as generally people want a fast boil. Lights are towards the low end as its rare for someone to want even 1000 watts of incandescent brightness.