Simply because you come across as extremely arrogant in your posts as if you're the only person vaguely experienced or qualified to discuss such matters.
The fact that you have no formal qualifications and are an amateur playing professional says it all.
Simply because your post needed clarification. You stated:
Somewhat over cautious, IMO, as there must be 10's of thousands of older APs out there that need to seatalk "network" powered up for the AP to work.
As I said - that's irrelevant as when properly installed the course computer (which is...
The autopilot control head should be powered by the course computer (technically it's not an ACU as that moniker is for the Evolution series) through a Seatalk connection so it's not really relevant. The SeaTalk to SeaTalkng converter should be powered by the Seatalkng backbone and the power...
Raymarine have made this more complicated than it needed to be really with various software versions supporting different SeaTalk data. A used converter on eBay for example may well not be able to connect to an autopilot without a software upgrade and the manual makes no mention of this. Whilst...
Raymarine are launching Axiom 2 as a replacement for their Pro series and are currently discounting the older units by up to 40% if you look online.
Axiom 2 Pro S | Chartplotters | Raymarine
Axiom 2 Pro RVM| Chartplotters | Raymarine
Solder connectors & heatshrink just require a heatgun. Even with postage the Wago connectors are still cheaper on eBay than Toolstation but if that's your preference so be it.