Selective Alignment Channel / Elemental Channel: Specialization or overcoming resistance?

Question

Building an oracle and looking through the Channel related feats I see stuff like Selective Alignment Channel (Channel can harm/heal Outsiders of a given alignment sub-type) and Elemental Channel (Channel can harm/heal Outsiders of a given elemental sub-type).

Does that imply that Outsiders[good] or Outsiders[air] usually wouldn't be affected by me channeling positive energy, that I'd need either of these feats to affect them?

Or does this just offer the flexibility to now target (Outsiders) by sub-type instead - bypassing my party in the process?

Channel says

Channeling energy causes a burst that affects all creatures of one type (either undead or living) in a 30-foot radius centered on the cleric.

I assume Outsiders are 'living creatures'. Looking at the Outsider creature type the only "special" rules seem to be about resurrection - not healing effects or channeling. Neither do I see anything in the sub-type description (say - 'good' or 'air').

So for now I assume I will affect Outsiders when I channel positive energy for example - and the feats just offer me greater control to target (say, in a scenario where I wanna heal 3 Outsiders[good] and cannot exclude a bunch of Outsiders[evil] using Selective Channeling)? Is that the use case for these feats?

Answer 1

When you channel positive energy you can heal ALL living things (enemy included, outsider, elemental, ooze, magical beast etc etc.) or damage ALL undead things. The same apply to channel negative energy (damage livings, heal undead). There are numerous feats that can help you to control what are you healing or damaging and, these feats, are:

Selective Channeling

Why is good? Because you choose every target of your channel

Why is bad? To be effective, you need an high charisma modifier. For example, if you channel positive energy in a fight with four enemies you need a 18 charisma score to exclude them.

Alignment Channel

Why is good? Alignment based channel. This mean you can heal your party/cohort and be sure none of your enemies will be healed at the same time (rarely, very rarely, a group of good characters will fight against angels etc etc). Don't need charisma score to function.

Why is bad? For a campaign like "Wrath of the Righteous" is probably the best channel feat you can pick. For campaign where the outsider are few and spared...well...is reaaaally situational. One feat = one alignment...and this is a big limitation.

Elemental Channel

Why is good? Read Alignment channel.

Why is bad? Read Alignment channel.

Answer 2

To be clear, an oracle that, for example, possesses the mystery Life and that uses the supernatural ability channel energy normally picks when she channels energy to, in that area, either damage all undead creatures or heal all living creatures. (It's always positive energy for the Life mystery's channel energy ability.)

And you're correct that living creatures typically include every creature except a creature that possess the type construct or undead. (Exceptions include any creature specifically called out as not being living and usually any creature that doesn't possess a Constitution score.)

To be extra clear, this means that creatures that possess the type outsider are usually living whether or not they possess alignment or elemental subtypes, therefore they're affected normally by the supernatural ability channel energy.

This means that the feats Alignment Channel and Elemental Channel are just adding flexibility, but in the right campaigns they add a lot of flexibility. That is, for example, normally that oracle above can't deal damage with channel energy except to undead, and both the feats Alignment Channel and Elemental Channel allow that oracle to deal damage to other creatures… if the creatures are outsiders possessing a particular subtype. (The subtype evil, for example, is often possessed by both demons and devils—relatively common foes of PCs.)

To be sure, these are not feats that, for example, every Life oracle must have in every campaign, but if the supernatural ability channel energy is both relevant in the campaign (i.e. it could deal enough damage to matter) and can be used consistently (i.e. you can count on fighting demons or fire elementals or whatever for the rest of the campaign), they are certainly feats to consider.

However, if that oracle above is more concerned with using the supernatural ability channel energy to heal, these feats are significantly less useful.