One big gap for Fujifilm shooters is off-camera flash. Other than putting an EF-42 flash on a long cord (a Canon-compatible cable is reported to work well), there are no first-party choices.
Yes, the X-Trans sensor is capable of low noise high ISO performance and the Fujinon primes are fast lenses. But what options are available for photographers who need supplemental light? If the requirement is for TLL flash control, then the long Canon-compatible cord is the only choice. But if manual flash will work for you, or is your preference, then I’ve found several viable options