My answer is that neither is ‘better or worse’, and that context is everything. However, GPA is considered the strongest indicator of collegiate success, and for good reason. Performance, commitment, and adaptability with (varying levels of) content/skills mastery, over time are indicative of the type of grit needed to succeed in academia.
High standardized test scores (SAT & ACT in the US) can show a type of commitment to excellence and specific content (or, in some cases, test) mastery. However, it’s compartmentalized, skewed towards higher SECs and some cultural practices, that it’s not comparatively predictive of the type of performance traits that have been indicative of long-term success. They’re not IQ tests, and for truly holistic purposes, standardized test scores have limited value in rooting out the types of “talent and potential” that an academic institution may be seeking.
My perspective on how “top colleges” view and contextualize “stats” changed a lot after visiting some of those schools and talking with admissions, and provosts/department heads.