[poet]

A PhD is a formal license to do research and it marks the start (not the end) of a lifetime of research. You need such a license if you plan to work at a company with a rigid corporate ladder or in academia.

The only additional reason to get a PhD besides the license is an increased probability of being in contact with peers who you can collaborate with. People often undervalue this but empirically it's pretty clear what the benefits of having at least one research collaborator are.

If you actually do decide to go for a PhD, you're going to need at least one strong recommendation that speaks to your research ability if you want to get into a top program. Your undergrad institution and GPA put you in the running to be sure, but admissions committees are looking for evidence that you can perform research. Recommendations that say "this kid got an A in my class and is a good student" don't really have an impact on your application either way.