There is an advantage in separating "protocol" from "binding" (in this case, "HTTP binding"). While REST is typically explained as an HTTP-only protocol, this is not the only possible "binding". I've successfully designed and implemented REST-style APIs using non-HTTP based RPC methods in the past. The main benefits in REST are not coupled with using HTTP GET/POST/PUT/DELETE but with the clearly defined model of resources, operations, client/server and limitations (e.g. statelessness) to make it a simple (but powerful) model.