[krackers]

There's one difference that if a program is run as tool call, the internal states and control flow are not visible to the LLM. You can imagine this being useful for "debugging" in a meta-sense, the same way humans can use debuggers to figure out where something went awry it might be useful for the LLM to "simulate" something and have access to the execution trace.

Of course you can also just simulate this by peppering your code with print statements, so maybe it's not that useful in the end after all.