That screen is specific to iCloud. Obsidian requires all vault files to exist in disk, but iCloud tries to save space by sometimes removing files from local storage and leaving placeholders, so Obsidian has to redownload them.
This thread contains both some comparison of the 2 services and some possible ways to refresh iCloud’s speed: "Waiting for iCloud to synchronise Obsidian configuration files…" - very slow every time you switch to Obsidian on iPhone