Why did nameko use RPC for Communication between Service?

From @radiegtya on Wed Feb 07 2018 05:31:02 GMT+0000 (UTC)

I think this is not issue, rather than just a question. Why did nameko use RPC for Communication between Service? Is there any issue when using REST? or RPC much faster for this communication purpose? Sorry I am newbie at microservices

Copied from original issue: https://github.com/nameko/nameko/issues/509