What is the utility of BTC? This is something hard to see.
Trustless, uncensorable, unseizable transfer of a scarce (fixed supply of 21,000,000) digital asset between more than 100 million distributed individuals accepted by 15,000 businesses, found on 500+ exchanges, with thousands of trading pairs. Not to mention with a huge first mover advantage.
Bitcoin has huge utility.
If you need to find out more about Bitcoin, you can pick up a copy of The Bitcoin Standard by Saifedean Ammous.