for mapping contests, people submitting .osu files instead of .osz files is a constant pain point, needing manual fixing each time so they can work with our contest tooling (to anonymise entries)

.osu file submissions are problematic because if the metadata isn't perfect, what audio file the submission is supposed to be paired up with can become ambiguous

sometimes, mapping contests have required multiple beatmaps for single submissions (example). the optimal way to handle this would be .zip files with multiple .osz files inside (enforced by external scripts as always), but since .zip submissions aren't a thing, the workaround has been template .osz archives containing multiple audio files and beatmap difficulties

an option to configure which file extensions the submission box allows would remove this jank