bitcoin is the perfect technical solution for preventing spam in anonymous systems like bitchat (or tor etc). ironically, many bitcoiners these days don't seem to understand that satoshi's big achieve...
Proof of work is just like what happens with the passage of time in the physical world. Each moment, the friction of atoms transfers energy from one source to another, enacting a toll or transaction cost. Satoshi mirrored the physics of the physical world and coded it into a digital form.