New to Panzer Campaigns, have many questions... Let's start with HQ's

[Mr Grumpy]

Although I can see there are advantages to trapping a HQ and not eliminating it, I think you would only do this if the formation that that HQ controls still has multiple units that are not trapped on the map, in this case you would deny all those units of the benefits of being in command range of the HQ by disrupting it and isolating it.

However as Rick said the trapped disrupted units still have a LOS and can provide useful intel to your opponent, however there will be situations where that is not important.

In the example you posted assuming that the units stacked with the HQ are the rest of the formation I would just eliminate the stack and bag the points.

As stated by the other guys an eliminated HQ will randomly re-appear at some point in the future and placed on a unit of its formation, that is assuming of course there is such a unit otherwise it will be lost forever.

Hope that helps...............