USDZ and glTF are two 3D file formats used for different purposes. USDZ is a subset of USD, created by Pixar and operated by Apple for iOS Augmented Reality applications. It is a zip file with USD and image files. glTF is a transmission format for 3D assets well suited to the web and mobile devices. It removes unimportant data for efficient support display and employs compression algorithms to reduce file size.
USDZ has some limitations compared to glTF, such as no geometry-specific compression, texture channel packing, and zip compression feature. However, it may have some advantages in terms of interoperability and scalability with other USD files.
Apple uses USDZ for iOS Augmented Reality applications, but Android does not support USDZ yet. Android has its equivalents, glTF and GLB, which are more suitable for web and mobile devices. However, it is possible to convert USDZ and glTF using tools like Reality Converter. Also, there may be differences in rendering quality and tracking performance between Apple and Android devices when using Augmented Reality.