Some psy's not good.

[East]

Not all psy should be good.
It is not necessary.

Or maybe someone is using it.
I wanted to learn how.

pain block - When should I use it? Reducing pain briefly can lead to pawn's death. Does that make the pawn a big buff to ease the pain? no. It would have been useful if the effect would make feel more pain.

chaos skip - Random is always dangerous. This spell is 1: 1 and is only useful when the enemy is a melee or animal But just burden or stun is effective.

manhunter pulse -There are no animals nearby even if you want to use it.

mass chaos skip -Random is too dangerous.

[carbon]

Painblock is obviously useful when you need to get a pawn who is downed back up and to safety, but don't have the time to do a proper rescue. Usually, they'll be down due to pain, so blocking it will get them back to walking for 30 seconds. My big problem with it is a downed psycastered can't painblock themselves.

I haven't ever used the others you mentioned and agree they have rather questionable utility. Although, I could see manhunter pulse being very effective against trade caravans, but I personally don't attack them.

[DuckBoy]

I've never used manhunter pulse, even as an artifact.  I honestly wish it would be a good way to raid other colonies, but raiding hasn't ever been worthwhile in the past.  Mostly because instead of having all the items they are willing to trade, they have 15 hats or something equally useless.  (I need to try raiding some royals!!) 

I use pain block all the time as an illegal psion: My first line of defense is a masochist with a psychic silencer and she tends to go down constantly due to the extra 20% pain on her, pain block gets her the ability to walk home. 
Her husband is a hypersensitive wimp, and he goes down every time he tries to train a muffalo, so they just painblock each other, entropy link, and teleport around the map whenever bad things happen. 

Chaos skip is super dangerous, but I haven't seen it jump through walls yet, if it did, it could actually be super useful in the right kind of trap.  I use it frequently when cleaning up after mech clusters: right after the gigantic turret starts hissing and you gotta gtfo quick. 

[DuckBoy]

This just in, Chaos skip totally goes through walls.  Could theoretically be used to get out of danger or trap enemies with sufficiently designed tunnels...