I agree with you completely, but there are people who aren't okay with big black rectangles on their roof (or are married to someone who isn't okay with big black rectangles on their roof). People tend to be emotionally attached to and have strong opinions about the appearance of their house, which is perfectly understandable. Rather than expect everyone to hold the same opinion about the attractiveness of solar panels, Tesla has made a product for those who think solar panels are ugly. If that means some people will install solar who otherwise wouldn't, I think that's great.

The one downside I can see is that HOAs may require the new kind of solar roof, even for those homeowners who would have preferred the old black rectangles (which would presumably be cheaper). Rules about what an HOA can and can't demand will of course vary by jurisdiction.