War and Conquering - newb question

[NineCoronas]

Hi! New poster, newish player

A few questions about conquering another faction:

If efficiency basically makes it so that your conquered bases will not produce any energy, what is the point other than using their minerals for production of new units closer to the battlefield & a healing ground for your units?
If you overtake an enemy HQ, are there now two HQ's? If so, will it impact the energy loss from inefficiency?
What does conquering an enemy faction gain the conquering faction?

I am playing as Gaian's currently roflstomping Spartans on the 2nd highest difficulty with Thinker and Growth mods installed (I think, I installed them in feb)

[Buster's Uncle]

They eventually assimilate.  Also, the enemy isn't getting the use of the base.

The enemy HQ goes away.

[NineCoronas]

When they assimilate, does that impact their efficiency? Right now I can't see any use for these bases long-term and am considering paying for a mass exodus of their population via colony pod lol

[Buster's Uncle]

Yeah, it certainly improves morale, and you get whatever efficiency is normal for a base you founded.

[bvanevery]

The population might be worth some votes to you.  You could put a Punishment Sphere on it, if you want to swell the population without having to invest in a bunch of expensive happiness infrastructure.

Siphoning off colonists is indeed a good use of more distant bases that aren't very happy.  Even bases that you founded.  However there comes a point where you really don't need more bases.  I think of it as more of an early to midgame strategy.

I often don't conquer inferior empires except to take just 1 base, so that they'll sign a Truce and stop pestering me with their warmongering.  Basically a demonstration that they're weak and I'm strong.  This makes sense if they don't have any bases worth having.  A base is worth having if it contains a Secret Project or is sitting on the Manifold Nexus.  Otherwise, distant bases are worthless IMO.

If they're distant Alien bases, I will build chemical weapons and completely exterminate them, with massive numbers of minor atrocities, including base obliteration.  You can do that without penalty to Alien factions, and also when you yourself are an Alien.  The stated reason is because you're not a part of the Planetary Council and have no idea what a U.N. Charter is.

If I'm human and they're distant human bases, I may seek to get chemical weapons legalized in the Planetary Council.  Then do the same to the distant humans.  It is important to do this to only 1 faction at a time however.  If you don't completely liquidate a faction, they have a nasty habit of finding a way to survive and eventually nukeing you!

You can also use chemical weapons illegally during sunspots.  Nobody will ever know you did it.  However the problem is the time window of sunspots, is usually not long enough to get the job done.  And once the sunspots lift, the long term penalties for illegal chemical weapons attacks are... quite onerous.  Visit the After Action Reports section of the forum if you want to find out just how onerous.