There’s one distinction that might be meaningful to some. From the link:
WiFi and Bluetooth firmware must be uploaded to the Realtek RTL8723cs on initialization, an optional auto-focus firmware (currently not used in any PinePhone OSes) can be uploaded to the rear OmniVision OV5640 camera
This means that any OS willing to use those features on the PinePhone will have to contain and distribute the blobs. PureOS doesn’t contain any blobs at all, and the Evergreen Librem5 doesn’t need the OS to have any.