They serve a purpose, for all those dollars!!
They did research when I served, a mere 50 years ago! These days, as part of DHS, not DOT, I can imagine that research is a dirty word compared to "projecting national interests" and the Commandant was summarily dismissed for predictable reasons. So I can't say what research, if any, is conducted these days. One can ask.
A recent comparison of CG and NSF breakers, the latter of which is now zero, is in this congressional report. Physical page 45.
https://www.congress.gov/crs_external_products/RL/PDF/RL3439...