If you're not going to read the replies or ignore everything in them I don't know why you're even bothering asking, but anyway:
It IS a bad habit they are teaching. This program teaches the language through repetition until it becomes reflexive, but including the vos forms it codifies them as being the way one speaks. Further, it teaches them as ustedes being formal and vosotros being informal. For most of the Spanish speaking world, including an entire hemisphere, that is not only unused, that is an outright lie.
Now please, actually try reading, thinking, and forming an argument this time. Just going "nuh-uh" isn't an argument.