This is complicated by the fact that Marines deploy as MEUs, MEBs and MEFs [1] which aren't "pure" echelons, but it's a rule of thumb and guiding principle more than a hard and fast requirement.
I've ALWAYS been annoyed by engineering organizations that don't think developers at the leaf nodes of the org chart need to know what's going on. Devs may not do anything with the info, but letting people in on what's happening seems to send the message that "management thinks you're important enough to hear what we're working on" and every now and again, individual devs need to make decisions that depend on these more abstract / higher-level goals.
1. https://en.wikipedia.org/wiki/Marine_air%E2%80%93ground_task...