It is possible to use the headset without a Bluetooth dongle. I used it like this for months, but regularly had problems establishing a connection with Cisco Jabber (VOIP solution). The audio quality or volume was also erratic, OK on some calls, more in the "troublesome" category on other connections. The assumption was that it was the headset, not the VOIP infrastructure.

For about a month now I have been using the dongle together with the official software for Mac, the "Jabra Suite for Mac". Since then, the connection and the audio quality have been good and constant.

yes is possible