It probably does piggyback off the sword ship.
There are MANY devices which use the unlicensed 2.4 GHz ISM band. (ISM stands for Industrial, Scientific, and medical) Examples are Wifi, BT, Zigbee, Microwave ovens, many cordless phones, and the list goes on. I think the phonak hearing aids also talk to each other across this frequency. HA fitting is also conducted at this frequency range, and but I think that is Bluetooth LE. It would be nice if it were much easier to get involved than having to buy a Noahlink wireless.
There are a great many proprietary uses of this band. It is fairly convenient and there is a lot of support for doing design work there where the basics have already been laid out for the designer.
Wiki page on ISM bands
WIki page on 2.4 GHz band
I guess I’m a bit more precise in my language as an electrical engineer. Saying something uses bluetooth to me raises expectations of what it can or can’t perform.
I saw a spec for airstream recently that went into the transmitted audio frequency ranges & etc, but can’t find it now. Maybe someone else has one handy.
WH