Why does it needs bipedal legs on a flat factory floor, does it need them to walk up the bus steps it takes to get to it's second story walk up apartment where it lives w/ its robot family?
People seem to misunderstand how easy it is to build a humanoid robot and how hard it is to program robots in general. Even if you build a humanoid robot that is perfectly general purpose mechanically, you will still need to program it like a computer that just happens to have arms and legs.
Considering that, either of two things would be sufficient for them to make general purpose robots:
* It will be one of their numerous business lines and provide substitutable labor for the others, not all of which are in car construction
* Considering they are in things from credit cards to railways to steel, they would like to add a new product line of selling robots to other customers
None of this is outrageously out of line. Various companies start with some business lines and end up with others. This is particularly common in Korea where Samsung wasn't always a semiconductor company. Hyundai themselves were in construction first. Closer to home, Amex was a logistics company. These things happen. Perhaps you are familiar with Softbank which was a PC software publisher and is now an investment company.
Second, I have to imagine that there are spillover effects for their other robots. Being able to make legs that are nimble is good for the ability to make grabber arms for industrial robots. So even if the humanoid product line goes nowhere, they could end up with better material handlers.