It is not irrelevant at all.marvalis wrote: So you had a skill that gives you 100% stun resistance. It is pretty much irrelevant if that resistance/immunity comes from a skill or from equipment. You still have/use it.
100% immunity to stun from equipment means that you will never be stunned. The free action (stun immunity) effect of movement infusions must be activated before a stun check is made in order to be effective, and can only be active about 35% of the time at most (with that char, or up to 70%+ with a different setup).
Unlike immunity from equipment, having a movement infusion inscribed provides no protection from surprise rush+dazes (as from a Naga myrmidon), cannot be relied upon to provide perfect stunlock immunity, and is rarely as effective against groups of enemies or in prolonged fights due to the saturation effect.
Also, the free action timed effect from my movement infusion was far from my main way of dealing with enemies that could stun. I generally killed them quickly enough to avoid them using stuns, or cured it with a wild infusion, or tanked through it (maybe with a regen thrown in), or used Providence, or teleported away, or ran away, (maybe using the movement infusion's speed boost, but rarely its free action), or kiled them despite the damage penalty.
tl;dr: having a movement infusion adds options for dealing with stuns. Having more options is better. Having 100% resist equipment/passive talents removes the need for those choices, but IMO is not necessary.