First thought is academic proof of work. Or to protect readers of news by alerting if text was modified. Thats what i know about. Its active research. Mostly anti-forgery tech.

I ought to read into the ether world better myself though. So take my words with a grain of salt.

A musing would be defending against malicious code injection ?

It seems the only thing that Eth devs do is create smart contracts to fund Eth devs.