Yes we as a company do, we mainly use X-H1 units now and our X-T2s are now our back up units. We only shoot the higher end Motor Sport events (not enough bucks in the small club stuff) and we are the PR togs for three F1 teams amongst our clients, so we attend every F1 meeting.
Loads of people using Fuji stuff for motorsport. All of the official FIA WEC photography by MacLean Photographic and John Rourke is done using Fuji gear. If I was ever going to switch to mirrorless for my motorsport photography it would probably be to Fuji