As a TYO-based flyer, I won't ever take Zip Air. For the cost, once you add on the baggage fees and the fact there's no beverages/food, the cost ends up being really no different than taking a major carrier.
Also, have heard from many other TYO-based people that the product is simply not that great. Seats very uncomfortable, in-flight streaming didn't work, leg room terrible etc.
It's mainly aimed at budget tourists hoping to cash in on the "Wacky Japan" travel craze that picked up in the late 2010s and was stalled by the pandemic.