Probably the big difference is that the pump has to run at heat pump speed continuously when you want the heat pump to operate.
With automation, the system will increase the pump speed to the necessary speed only when the heat pump is on.
Other than that, it's mostly convenience.
Without automation, you're still mounting a subpanel and a SWG power supply and a timer.
The labor involved is the same either way.
I think this is all stressing my wife out, she thinks I am being a pain in the butt by not just going with what the PB is recommending....