I recently got a nice office chair for Christmas with heated massage functionality and it uses a barrel plug to power it but I have to be super careful to not pull it or damage the barrel connector in any way. I wish there was a magnet conector for these things in case of a yank pull and was wondering if anyone had heard of some adapter like the one I pictured above.
No. They are indeed used for power only.
But technically you could use them for data or small signal.