You don't need a blockchain for this. A commit to the Linux kernel, once accepted, practically will never be removed from history, since it's been copied so widely and would require so many people to agree.

And isn't this also how ordinary accounting systems work?

The place where it breaks down is that Bitcoin is for anonymous people who don't trust each other. With fraud there is no forgiveness.

In many other systems, people are not anonymous and mistaken transactions can be reversed, using the court system if it comes to that.