Yes, there are a few medical cases where fMRI makes good simple basic sense, and TBI/Concussion sounds immediately like one of those to me. I seem also to recall them being useful in some cases prior to brain surgeries and the like.

This all makes sense because fMRI tracks metabolic activity via oxygenation changes, which is much more clearly and plausibly related to tissue health and recovery. In these cases, it is also most likely being used within-subject (i.e. longitudinally) to make comparisons to baselines, rather than in an attempt to make speculative inferences about the mind using groups of people, and likely is a simple comparison to baseline rather than bespoke statistical analyses relying on questionable assumptions about the BOLD response being related to overly-specific kinds of neural activity.