The vast majority of work done in space is already done by machines.

Humanoid robots are potentially useful when operating in human environments, but that doesn’t really apply if we’re never sending humans to these locations.

Agreed, for space being humanoid is optional. Legs are superfluous for a start. However the issue with current automated systems we’re sending out there is they are function specific, and not very adaptable to novel or unanticipated activities.

This is why sending humans is often advantageous, we can do lots of different and new things. The ideal multipurpose space robot may not have to be humanoid, but it would need to replicate or ideally exceed this kind of flexibility of function.