I found this whole issue confusing. If the balloon was a deliberate attempt at spying, why was it made with solar panels and not batteries? That thing must have

I found this whole issue confusing. If the balloon was a deliberate attempt at spying, why was it made with solar panels and not batteries? That thing must have had the radar cross section of a school bus. Also why wasn't the balloon envelope clear? It just seems so odd to assume this was supposed to go undetected.