Parallel execution - Grid vs Appium Only (Android)

I have tests running on real devices in parallel using only the appium server. Is there an advantage to using selenium grid? I ask only because all examples I have seen for parallel testing show people using selenium grid rather than the appium server only.

Thanks.

I have used selenium grid to run parallel tests in actual devices. I didnt see any working example of appium parallel execution without grid.

Which is mentioned in docs
http://appium.io/docs/en/advanced-concepts/parallel-tests/
I have gone through the content in link but didnt find anything which helps.
need more info.

@boyleheights / Anyone having code for the same please share.
I just wana see how its done.

After that i may be able to answer your question.