The one full bike fit I paid for I got because I was ordering a made-to-measure frame, so I guess it worked for me because I am comfortable on the bike and couldn't have gotten it otherwise. The bike was assembled by another shop (where they'll arrange to spend an hour or so fitting your bike if you want to pay for that, but don't take measurements to build a frame), where an assembly fitting that took about an hour was included. However, I have since lowered the stem, after which riding out of the saddle felt more smooth and natural.
Aside from the time I had a misaligned cleat, and the times I've ridden a Citibike where the saddle wouldn't stay up, I've never had the feeling that a less than ideal fit has led to any discomfort or serious degradation of performance, but I have often had the feeling that with a perfected fit, things would "fall into place" more naturally, and things would run more smoothly. But I also feel that I, myself, adjust to the varying arrangements of bikes I ride, and after a while, what felt perfect now feels a little off, and what once felt off now feels perfect.
Last edited by kbarch; 06-13-17 at 04:52 AM.