There are myriad other issues which could be improved or alleviated by bike fit. It could be knee, lower back or saddle related pain. It could also be something the rider thinks is unfixable or not important enough to warrant investigation.
Another quick case study if I may.
A few days ago, I had a client who had booked in to check her set up having just bought a new frame. The fitting was to check her existing set up and make recommendations on stem length, bar width and spacer stack for the new bike. Through the course of the pre fit interview, we identified an issue with saddle soreness, as well at persistent right hand numbness. The rider in question had pretty much accepted the hand numbness as part of cycling. She had already tried a huge range of saddles and had almost resigned herself to having to manage saddle sores with time off the bike.
During the physical evaluation we discovered a significant restriction in hip flexion range on the right. This, in conjunction with lack of skeletal support from the saddle was the cause of numbness in the right hand. Saddle pressure mapping helped show that a narrower saddle improved bony contact and pelvic stability.
A shorter crank (down to 160mm from 170mm) helped keep the right hip away from the restricted part of its range an stopped the right hand being involved as much in keeping everything still.
A referral to a physio to further investigate the hip issue is the next step here.