Interesting, I didn't think about this! Although it can work, using logs or APM without infrastructure monitoring was not a design goal for the agent. For this use case, I'd investigate using https://vector.dev/ instead of the full agent.
Normally this wouldn’t be an issue and would be more cautious in production, but was using the Agent on some Dev machines to ship logs and was surprised to see Host metrics from them unintentionally along with the bill.