[latchkey]

Not bitcoin directly, but WBTC (the tokenized version of BTC on Ethereum and other chains), can be used in DeFi to borrow any other token, against it.

It is a fantastic use case because now you can borrow up to your collateralized limit, without talking to anyone. Thus enabling you to make pet rocks work for you.

DeFi really is a great usecase. It is of course, early days, meaning that it can be high risk, but it can also be high reward.

Lastly, this is one of my favorite comments here on the subject of usecases: https://news.ycombinator.com/item?id=26238410