Why do (most) strobes use Xenon flashtubes instead of LEDs?

[encrustingacro]

I remember hearing from a Backscatter video not to use LED video lights with a strobe/burst function for underwater photography. They stated the LED ones don't use capacitors which means the flash time isn't fast enough, and the LED isn't as bright. Well, why don't LED strobe manufacturers use capacitors, and aren't LEDs brighter per watt of energy used? Is it because the capacitor might overload the LED, destroying it, or that LEDs with the same brightness as a Xenon flashtube are too expensive?

 

[Barmaglot]

The difference in prompt brightness between a Xenon flash tube and a comparably sized LED array is several orders of magnitude. Several years ago, someone on Wetpixel did a comparative test between a Gates GT14 and a Sea & Sea YS-D2, and the conclusion was that an LED light would need to emit something like half a million lumen to rival a mid-range strobe.