Agree with you both – humanoid robot not needed other than for companionship, etc. Non-humanoid, specialist types surely much better at what they do. Musk’s plan seems just a bit of bigging-up.
Using robots as space explorers and terraformers certainly makes sense. However, as their processing powers increases, and with necessary self-repair and improvement capabilities, how long before they develop real AI? A self-aware, cognitive machine-intelligence would probably look at human history and decide that it really ain’t a good idea to let us colonise other planets. Anyway, given the distances and immense timescales involved in sub-light speed interstellar travel, we’ll likely be extinct before they even get to another system, let alone travel back here.