Immune to fatigue

[Shadow_Charlatan]

What are the benefits from having "Immune to fatigue" ? (source : Serpent in the Sun revelation)

[Lincoln Hills]

The Fatigued condition is in the CRB, and the various ways it can be imposed (forced marches, resting in medium/heavy armor, hypothermia, heatstroke, recovering from barbarian rage, certain spells, etc.) pop up here and there. In every case, you don't suffer the condition or its associated penalties (which I believe are -2 Str, -2 Dex, and inability to run or charge). Is there some specific question you have about the immunity?

[Zhayne]

Big benefit: Rage cycling. Enter rage, use 'once per rage' abilities, turn rage off, turn rage back on, use 'once per rage' abilities ...

[Pizza Lord]

Similar to having the Endurance feat, which lets you sleep in medium armor, you don't become fatigued doing it and you can even do it in heavy armor.

[Squirrel_Dude]

Your character doesn't have any ill effects from not sleeping, which helps to prevent "an assassin sneaks in a kills you in your sleep" type events. Fatigued is also a really annoying condition to have applied to you.

[SlimGauge]

Protects from the Touch of Fatigue cantrip. Some Magi get this added to their spell list (there are ways) and then spam it at low levels with Spellstrike.