I am using this api for music player[0] in the browser. Biggest share of my users are using Chromebooks, where besides Android apps are not much alternatives. If this API was not available closest thing would be to make an Electron app, which has much more broad system access to users device than a website using showDirectoryPicker.

Regarding security I think Chrome got right balance on this: you always need to select folder, sensitive ones are excluded, on repeat visits if you try to access a file, it asks you permission again, you can't get full filename paths and so on.

[0] https://github.com/minht11/local-music-pwa