As a value proposition, you have an initial cost of $50-$300 (depending on what kind of reception you get and what features you want, like DVR), but if you consider basic cable these days being $20/mo it's a nice way to save money on the one thing you can't get fully yet - live news and sports. Also, if we are allowed by the broadcast overlords, you can DVR movies and tv shows and keep a library for yourself without another subscription.
I have an antenna at home but I don't use it primarily because I get poor reception. ATSC 3.0 has been proven to fix this in many cases, so I'm hopeful this could be a great way for many people to save money.