As I recently retook my Scrum certification, I went over some key differences between PMI and Scrum project management.
Completeness vs complexity
From a mid-level managers perspective, PMI certifications cost more, which does affect the bottom line once You get to scale. This may however be the least concern, as any successful business orients at net profits and not costs.
PMI-ACP offers a broader outlook onto agile methodologies. Which is not necessary per se, as the Scrum guide alone, when implemented holistically, has certainly been more than enough for many successful projects.
Experience vs franchise licensing
The people behind Scrum.org wrote the book on the subject, and the manifesto. And participated in multiple successful large-scale projects. the PMI-ACP certification was introduced in 2011, ten years after the agile manifesto was published. Some say that happened due to PMI loss income as industry shifted away from traditional project management frameworks.
I personally have had success with both having teams get certified in-house, without the need for an external authority, and having people take the Scrum.org online-only certification. At the end, it was strategically enabling developers to own the project that made the real business impact.
Further reading:
PMBOK® guide versus SCRUM mastery points of convergence and divergence
https://www.pmi.org/learning/library/pmbok-guide-scrum-convergence-divergence-8089