Idealistic view: BTC is used to create peer-to-peer marketplaces (OpenBazaar [1]) and the underlying blockchain tech can be used to implement smart contracts that can automate systems and remove humans from the loop (Samsung/IBM ADEPT [2], Filament [3]).
Realistic view: BTC is used as a speculative hedge, and to evade currency controls in China.
Can someone explain why it's a good idea to use blockchains for IoT? The example they give is of a smart washer checking to see whether the washer is under warranty when it detects a part is about to fail... but why on Earth would a blockchain be better than any old database maintained by the company? Why on Earth use a distributed ledger?