The issue with Gliders on Grounded is an active item like a sword or a shovel which you can use by having it on your backpack, but instead, you need to equip them on your paper doll for them to be usable.

On top of that, they break after some use, so it's common for you to hastily grab on dandelion from your chest, drop on your backpack and not properly equip it, or simply jump from a cliff without having one at all.

I believe everybody died at least once from glider shenanigans on Grounded. Me? Now I double-check before every jump.