According to KID/PRIIPS regulation in your opinion
in which case should PCA (as from article 23) be used?
Just for structured products and bond-related products or also in other cases? Do you have practical examples where you would use it?
Typical uses of PCA in the industry are for modelling:
For the above cases, the first three Principal Components typically captures more than 95% of the curves moves, which makes it a powerful tool when it comes to curve modelling.
As Structured Products are a combination of an option component and a bond component, PCA would be used for the modelling of the bond component and more generally for bond-related products and, as I mentioned above, forward products.