I am making a liar character. He has False Priest archetype, Rashasa bloodline, Charisma pumped up as far as I could and as his first feat racial Realistic Likeness. So far so good.
Now, sometimes concealing what spell you are casting, or even that you are casting at all is tempting. So I looked for a way to do that, and found two:
Conceal Spell has more steep requirements and slows down casting, but it looks like mechanically more beneficial.
Cunning Caster is simpler, has easier requirements and only requires Bluff, but also has a lot of -4 modifiers that stack with each other.
I am not asking which one to choose. I am asking for context. I don't have books they came from (Ultimate Intrigue and Heroes of the Street), so I'm asking you:
Are these feats supposed to be generally available and useful? Or should they be used only within specific campaigns or together with some other set of rules? Does using them without the rest of their respective books make sense, assuming published modules that only require Core Rulebook and Monster Manual?
Official quote from authors would be highly appreciated.