Nearly actually Watts = Volts x Amps x power factor correction however in real terms more looking at inrush. So a LED lamp needs a power supply to limit the amps to the LED, the normal method is to use a switch mode, or pulse width modulated power supply, and these normally first turn the supply to DC and charge a capacitor with it. So they need on switch on more power than when running, not all, some use a capacitor to limit the current, so we look at between 50 and 110 lumen per watt, and the lamps which are more efficient in general have a larger inrush.
So 30 switches each turning on a 100W LED the time taken to switch the switches on, means inrush not a problem, one switch with 30 x 100W LED's is likely a problem.
Even incandescent lamps have an inrush as a cold filament has a lower resistance to a hot one. Also because a lamp says 58W does not mean it uses 58W, I was given a job of lighting a tunnel, using 110 volt fluorescent tubes at 58W each that is approx 0.5 amp, so should run 32 so leaving a bit to make sure, used 25 lamps in a string. The 16A MCB tripped, and when I measured with a clamp on meter found using around 22 amp. So experimented with one lamp, and there was a 127 volt or 110 volt taping on the auto transformer, moving to 127 volt setting current dropped but last 5 failed to start, so first 20 set to 127 volt and last 5 to 110 volt and it used 16A.
With 230 volt fittings we don't have option to change tapping, however with a HF ballast it actually uses less than 58 watt, more like 54 watt, which makes it hard to compare fluorescent to LED as although the tube is rated 58 watt at 5200 lumen with a HF ballast it uses around 54 watt and produces 5400 lumen when installed, they are claimed to last same hours as LED, but the light output degrades more than with a LED, however also far cheaper.
But there is two very different reasons to light things, one is to see what one is doing, the other is to look nice, and LED lights that change colour can drop to 25 lumen per watt or lower, so can use as much power as tungsten, so although 13A would light a very large garden to walk around it, to light up the folly imitation castle with lights changing colour trying to outdo the London bridges can use a lot of power.
I think we all think of our own garden when answering this question, but my friend has 20 acres of woodland, to light that would take some power.
