Can the glTF format be used for 3D printing?
No, gltf is not a format that slicers accept commonly, and indeed, it is not even intended to be reverseable in the 1.0 format version. This has changed a little for the 2.0 standard. Some programs that allow exporting into the sliceable stl and  obj formats can also import gltf:


blender has an importer plugin - more  info here
SketchUpp has an importer plugin


You have to be careful though: formats like dae or stl are meant to transfer 3d objects usually without the loss of information or with just a minimal loss (stl, for example, does technically not contain a scale natively), while gltf is end users and does not contain all the information. This can lead to models getting distorted and destroyed on importing them into a rendering or modeling software.