OBJ is a text-based format, which makes it larger and slower to load and save compared to binary formats. The CPU has more work to do to interpret a text-based format compared to a binary format. Also, OBJ's accompanying material file (.mtl) does not support PBR materials, which limits its usefulness in 2021 (except for retro-looking games).
glTF 2.0 exists in both text-based (.gltf) and binary (.glb) formats. I recommend using .glb whenever possible in production, but exporting in text-based .gltf can be useful for troubleshooting purposes.