There is no real world use. It probably wouldn't even exist without Grayscale.
It so happens that the consensus of the majority decided to stick with Ethereum rather than classic. But still no single person or entity gets to decide.
The Ethereum foundation kept a huge stash from the pre-mine, so you'd have a hostile actor with a large position on your forked chain, enough to crash the price of any nascent chain. This combination is a governance model rooted in game theory.
Ethereum Classic shows pretty well how this works in practice. There was controversy around the DAO, yet no fork could be kept functional. It is a Grayscale project which they will keep around as long as people are willing to speculate on it. Nobody pretends it has any real use.
This is completely false. The Ethereum Foundation has less than 0.5M ETH, or less than 1% of the total supply.
But Ethereum Classic and Ethereum share a common blockchain history and it proves that the community doesn't always follow blindly the proposals of the Ethereum devs.
That event (a part of the community splitting of on a hardfork and forming Ethereum Classic) has affected the governance of Ethereum ever since. Not directly, but indirectly.
Every hardfork is now checked for contentious changes very thoroughly. The last major change that didn't make it because of that was the proposed change to the mining algorithm (granted, ProgPOW had other problems as well).