I'm not sure why you're asking about the Philippines specifically. A prenup has to be reasonably fair, and both parties need legal representation. Where you marry and who you marry doesn't matter. Where you divorce is what matters.

Got a prenup... not divorced. So I didn't answer.

Whether it works isn't easy to answer, because it also depends on exactly what's written in the prenup. Some clauses can hold up and be accepted, while others can be rejected for violating a higher law. The only people who could judge whether it 'should' work are people who've studied law.

What's the point of a prenup in a country that doesn't recognize divorce?

I never told my second wife about my investments or my holdings in a third country, so she never bothered. I was living the FIRE life and she thought I was poor. You know how you can outsmart your dog by hiding the ball behind your back? Yeah, same thing.