PA is measuring something real that SPF doesn't. SPF grades protection against UVB — the wavelengths that burn. PA grades protection against UVA — the deeper-penetrating wavelengths that drive photoaging and pigment and that don't announce themselves with a sunburn. The PA scale (used in Korea and Japan) is based on a lab measure called PPD, persistent pigment darkening; each additional plus is a higher measured UVA protection tier, with PA++++ the top band. Western equivalents exist — "broad spectrum" in the US, the UVA-in-a-circle mark in the EU — but PA makes the UVA grade visible instead of pass/fail.
Should you care? If your concerns include aging or pigmentation, yes — UVA is the main culprit there, and UVA protection is what lets pigment treatment hold its gains (https://www.jaad.org/article/S0190-9622(14)01870-2/fulltext). Between your two hypotheticals, they're protecting against different things, so "worse" depends on the axis — but a high-SPF, PA++++ product covers both well, and modern Asian sunscreens routinely deliver exactly that.
The honest footnote: the rating on the tube assumes the tested application amount, and most people apply a fraction of it — for a face, aim for roughly a quarter teaspoon (the two-finger guideline is a decent proxy), and reapply during real sun exposure (https://www.aad.org/public/everyday-care/sun-protection/shade-clothing-sunscreen/how-to-apply-sunscreen). A generous layer of PA+++ beats a stingy film of PA++++ every time. And if melasma is in the picture, tinted formulas with iron oxides add visible-light coverage no PA rating captures (https://pmc.ncbi.nlm.nih.gov/articles/PMC8887048/).