Bad for anybody with disabilities who require the space, bad for people with clastrophobia.
All I have to say is eeeew, hard pass. I do not want to be on the lower seat. Especially after someone has just eaten airline food.
OP here: https://www.reddit.com/r/mildlyinfuriating/comments/142mciv/honestly_why_bother/
You can book an upper seat for a low price of $15.99! 🧑🏽✈️
(and sign a waiver in case you sustain any injuries trying to walk up the stairs during a windy route)