[jonnydark]

It verifies that you're actually connected to the server and it is listening to you rather than just some dumb box that keeps nodding and replying with "OK" with glazed over eyes regardless of what you say.

[jon-wood]

So instead you could be communicating with a marginally less dumb box, which nods and replies with whatever you said instead?

[dferlemann]

If it can reply whatever you requested accurately, then the established 2-way communication can be said to have the same quality.