It appears that iOS developer Guilherme Rambo has been able to confirm the upcoming always on “Hey, Siri” feature on the new iMac pro. He was able to dig into the BridgeOS 2.0 package from Apple and find the setup process that will guide users through the initial voice enrollment process.
“Hey, Siri” allows you to access Siri simply by your voice, instead of having to invoke a keystroke or clicking the icon. The feature has existed for iOS users for some time now.
Siri came to the Mac only recently, and it still has lacked behind its mobile counterpart. There are several limitations including “Hey, Siri” and HomeKit support.
“Hey, Siri” will only be coming to new Macs, like the iMac Pro. It will rely on a BridgeOS device, such as the A10 Fusion processor debuting in the iMac Pro. The Apple designed A-series chip will always be running, even when powered off. This always-on functionality will allow to handle these background tasks, like listening for the “Hey, Siri” voice prompt.
One big difference between iOS devices and Macs, is that your iPhone or iPad is often a personal device. Computers can often be shared by a whole family. That means Apple had to reevaluate how “Hey, Siri” would work. For the first time, multiple voices can be enrolled on the same device. This would allow any user of the device to activate Siri through their voice.

How often do you use Siri on your Mac? Does the including of “Hey, Siri” make the iMac Pro more enticing?