Whats the point of a first contact war?

[Cryten]

I tried a first contact war, you cant take territory or destroy the outposts. Is the only use of first contact wars to reduce the aliens fleet power?

[Meewec]

it's honestly probably just a forgotten mechanic from previous versions of the game. if you were quick enough in the past you could have potentially destroyed a starbase and eliminated territory it was claiming but now the best you can hope for is either killing some of their fleet or maybe a science/construction ship. plus you can scare them from expanding a certain direction until they research communications

[Malaficus Shaikan]

Either to get some early game vassals or because you are playing a total war empire.
Feudal empire's can use vassals to cheap expanding tools and early game meatsheilds.
And total war empire's just want you dead and dont care about the poltical fall out.

[Elitewrecker PT]

^^
First contact wars is the militarist policy where you can shoot against any empire you meet before you decode the communications, how does that get you vassals?

[MadArtillery]

Ive used it to secure a choke point against two alien empires before. Was particularly good because one turned out to be a driven exterminator

[Zuul]

First contact wars are useful depending on how attentive you are and how far away your fleet is. With travel and build time you have about 120 days to target and destroy an unknown construction ship before it can finish building an outpost from when it arrives in system.

Also, if there is a specific choke point you absolutely “must” have...beeline to it with a survey ship on explore then backfill with survey. Meanwhile move your fleet to the choke and wipe out all comers. If they can’t survey the entire system you never even need to worry about the construction ship.

Meanwhile, the only penalty for you is a mild diplomatic penalty once communications are established.