This is cool and all, but Wi-Fi and Li-Fi are equally "light-based", it's just using different frequencies. A higher frequency means potentially faster data transmission, but at the cost of faster attenuation. We see this with 2.4GHz vs 5GHz wifi already, and this sounds to me like a more extreme version of that
Yes and no. It's both electromagnetic waves but the frequencies are very very far apart. So far, the techniques we use to emit and receive them are fundamentally different. Their propagation and transmission characteristics are also very different.
Also, the data transmission rate (in theory) only depends on the bandwidth of the transmission channel, not the absolute frequency. But there's more "room" for large bands at higher frequencies, of course.
Idk. Lifi uses actual light waves which are quite high up the spectrum. For sure Wi-Fi and Li-Fi are both electromagnetic waves, but light itself is a very small section of the EM spectrum. Above that wavelength you get ionizing radiation that gives you cancer and below that is harmless non-ionizing light and radio waves.