Good ways to use this

[Atalius]

I'm a lot less experienced with PF than a lot of the veterans on these forums, so I come seeking your advice. I came across this feat, I'm sure there is an excellent way to utilize it, but due to my inexperience I'm not quite sure how it could be used optimally. Does anyone know how and why this feat would be used:

MELODIOUS SPELL FEAT 8
Trigger You begin casting a bard spell that has a
maximum of 2 spellcasting actions.
Add a Verbal Casting action to the casting of the triggering spell and attempt a Performance check against all observers’Perception DCs. If your Performance check is successful against an observer’s Perception DC, that observer doesn’t notice that
you are casting a spell. This conceals only the spell’s spellcasting actions, not any of the spell’s physical effects, so an observer might still see a ray streak out from you or see you disappear if you turn invisible.

[Edge93]

Literally only if for if any reason you are trying to cast without anyone knowing you are casting. Sneaky or social stuff mainly, as written it might prevent enemies from getting an AoO on you if it works since they don't realize you are casting, talk to your GM there.

Though it's not really optimal for that as the extra action can be used to step out of threat range usually. But if you're cornered or inside a large reach it can be good there.

[Raylyeh]

Yeah it looks like it could potentially stop a reaction. The primary use is for what it says it’s for. In PF magic is blatant when used. Reciting strange incantations, glowing runes floating around the caster and what-not. So, as an example, casting enchantment or illusion spells in a social situation without others noticing can be problematic without this or a similar feat/ability.