The purpose of the Free Fair Zone was always to facilitate Trax as an 'urban circulator' to shuttle visitors/tourists/convention-goers around downtown, and facilitate the 'out of office lunch'. No one has to buy a ticket, fool around with the ticket machines... just wait, hop on, hop off.
It's the reason that the main line goes from Sandy to Area, rather then Sandy to University--both the University Line and the Main line proceed through downtown, effectively doubling frequency, so that the average headway north of Gallivan is only seven minutes.
I'm not a big fan of TRAX in downtown. Once I'm in the area, I tend to get off an walk. Once, coming from Sandy, I rode the Trax around the northern arc to get to the Twilight Concert Series in Pioneer Park, at 300 W. and 200 S. It was slow going, and seemed to take forever. The UTA schedule claims it's a 12 minute trip, over about 7.5 blocks, giving the TRAX an average speed of about 5 mph going through downtown.
I was displeased when Rocky Anderson demanded that UTA add two stations in the TRAX extension to the Salt Lake Central Station. Every station adds five minutes to travel time, for deceleration, boarding, waiting for the signal to turn green, and acceleration. Having two stations instead of one saved about a blocks worth of walking time, and added half a blocks worth of travel time.
The next concert, I got off at Gallivan Center, and walked the four blocks west. It took about 15 minutes. I had plenty of company on the walk, so I expect a lot of people were doing the same thing. And I was coming from Sandy, so I didn't need to make a transfer. Even with a 7 minute headway, that's a 3.5 minute waiting time, giving TRAX a negligible advantage over walking.