I earned my CGFM after working in the field for several years. I cannot say it has been particularly helpful but it doesn’t hurt. The cost and effort to gain certification is not excessive. As might be expected from a credential sponsored by accountants, the CGFM leans very heavily on bookkeeping with camparatively little (ie. none) empahsis on the higher level thinking required for budget analysis. Nevertheless, It may be more helpful for someone early in their career who needs to get credentials quickly.
Depending on the focus of your career interests, you may want to get a CPA to demonstrate your bookkeeping skills.