Not enough leg room in economy to actually use it

You could probably use it in the business class or economy comfort, but in regular economy class, you just don't have enough room to use it

There is not enough room for you to stretch out and get any support to your legs.

There was not enough room between my seat and the seat in front of me to use it.

The seats are very close together, and I barely have enough room to lean on one side an fart, much less hand this thing on the seat in front of me (how, I can't imagine) and put my legs in it, as pictured

Usually, my knees are pushed up against the seat in front of my, and I have a personal bag under that seat, so there is usually barely enough room for my size-12 feet

There just isn't enough room