I am an open-book for the most part and do not shy away from honest questions.
Same thing for the glider, basic glider can save you from dangerous falls yes but those falls are usually falls that you weren't trying to progress anywhere to because vistas and objectives typically don't permit them, same for mounts too.
Someone can carry you yeah, but it makes no sense trying to obtain it, even if you did.
In a hollow fire only the inner walls of the fire are burning and it cannot heat iron much over a red heat.
Volatile matter is driven off as a thick smoke.
This insulating layer also protects the firepot from the intense heat of the forge fire.