With the default configuration in Electron, renderer processes (which should not have access to system resources by default) can gain read/write access to a nearby bluetooth device. To reproduce:
await navigator.bluetooth.requestDevice({acceptAllDevices: true})
If an Electron app loads remote or untrusted content in a renderer process (which is normally fine, as the process should not have any privileges), the remote content would have read/write access to nearby bluetooth devices. The impact would then depend on what devices the user has nearby.