It is a largely failed experiment in making internet cash that has turned into a speculative bubble not unlike Tulip Mania.* The intent was to be able to make small payments online without attaching your name and other personal information to it, much like you can use cash instead of a debit card to pay for things without giving your name. But that vision really hasn't materialized. Meanwhile, it has been bid up crazily and become insanely expensive, like the aforementioned tulips.

* https://en.m.wikipedia.org/wiki/Tulip_mania