I am not necessarily advocating an MBA. But this line of argument can probably be applied equally to many if not most degree courses. Especially applicable if you're talking about a degree at a 'better' university vs one that might be cheaper or where you may be eligible for scholarship.

If you want to learn most things there are probably better ways of achieving it. You can gain most knowledge almost free. But Universities give you a bundle of people, a framework, deadlines, teachers and the rest that amounts to something that people don't tend to get elsewhere. It also works without the highest possible level of motivation. While not glamorous, that's valuable.

As far as needing the knowledge, it's a judgement call. There are courses out there with more of a small business focus. It's definitely not a prerequisite, but taking time & resources & dedicating them to gaining knowledge in this area can produce value.