This happens quite regularly in the world of margin trading.
Imagine the following:
1. I own ETH, and want to hold my ETH position so I can enjoy price increases, but I need liquidity to live my day to day life and, well, it's hard to pay for things with ETH. 2. Instead of selling ETH and exiting my position, I put ETH up for collateral and borrow a stable-coin (like DAI) against it. That way, I maintain my price exposure to ETH, but have liquid cash to use for my day-to-day needs.