Because it misses the point. The problem is not the model being in a cloud. The problem is that as soon as "untrusted inputs" (i.e. web content) touch your LLM context, you are vulnerable to data exfil. Running the model locally has nothing to do with avoiding this. Nor does "running code in a sandbox", as long as that sandbox can hit http / dns / whatever.

The main problem is that LLMs share both "control" and "data" channels, and you can't (so far) disambiguate between the two. There are mitigations, but nothing is 100% safe.

Sorry, I didn't elaborate. But "completely local" meant not doing any network calls unless specifically approved. When llm calls are completely local you just need to monitor a few explicit network calls to be sure.