These local device to device file transfers needing nothing else, will be used with your Google account and services involved. This give the potential of recording metadata of files transferred (device/date-time/filename/file fingerprint) in these, as well as possibly even passively usurping device associations, powered-on/activity times, and locations by proximity.

They are far from the first to do this, even in this form, and the smart-phone Android/Apple per-installed privacy leaking similar services have already by pervasive for a long time.