Newbie wall switch question

I have a three way light circuit in my stairway. Am I correct in assuming that if I replace the two existing wall switches with something like the Jabsco/GE 46202 and one add-on 46200, that normal/manual light operation remains but that my HassIO system can also turn the light on or off? Do both switches pair with the controller or just the line side switch?

Thanks in advance . . .

Yes, but you will only have to replace “the last in line” before the light… then the current wire to the light controls the input and homeassistant can also control it then.

I take that to mean that I only need the ‘add-on’ switch version of the two devices? That would make sense as the smart switch only needs to mimic one end of the two switch circuit. The Jasco manuals seem to claim that damage is possible if one does not use both their line and load side (add-on) devices.

EDIT - so, to close this out, I have discerned that the Jasco add-on switch will not communicate on its own, and requires the line switch to function with HA.