Fair point about criticisms and public perception. But what matters is not top speed, but
average speed.
For example, the UTA 2X bus, the 200 South Express (no stops between central station and 13th east) will get you from Salt Lake Central Station to the University Medical Center in 30 minutes. I am too lazy to measure the exact miles by road, so I'll use the direct route a gondola could take - down 200 South then straight across the U campus for a total of 3.75 miles. So even though the top speed on 200 East is 25 miles per hour, the average speed is 3.75miles/0.5 hours, or 7.5 mph.
Let's imagine the gondola makes only two intermediary stops between Salt Lake Central and the Medical Center, one at Main Street and the other at President's Circle. This is safe to assume because gondola stations are huge expensive affairs, slightly more complex than building an elevated rail station (this is the main reason it isn't fair to compare the S-line to a gondola, because they would serve different transit niches). So let's just say that for simplicity's sake, we use the 10 mph top speed also as the average speed. That same distance of 3.75 miles would be traveled in 22.5 minutes, or 7.5 minutes faster than the bus. Which doesn't sound like much, but considering what effects traffic and weather can have on the bus schedule, I still think it's a good idea.
Add to this my belief that a gondola built in SLC would be superior in quality than the urban gondolas in South America, and that our's would have a higher top speed. Go 3.75 miles at 12 mph, and the trip can be accomplished in 18 and a quarter minutes. Raise the top/average speed to 15 mph, and you get a trip time of 15 minutes. Twice as fast as the bus, because the average speed is twice as fast, even though the top speeds differ.
That is why in a few limited point-to-point situations, gondolas are a very good choice. Even the best choice. Obviously you can't rely completely on gondolas (which is why the Wire video I embedded above is mostly fantasy), but you can use gondolas to directly link end locations better than buses or streetcars or any multiple-stop system can.
EDIT: I was responding to Future Mayor, but L.W. beat me to it.
EDIT OF EDIT: I got so enamored with my own idea that I made a terrible map to post on this thread. Here it is.

Obviously the thin white line measuring out the distance is the cable, and the four red dots are the stations. One at Salt Lake Central built above 200 South, one at Main Street straddling the intersection (with walkways descending down both sides to the convention center and to Galivan Plaza), one at the University in the open space at President's Circle (politically impossible, I know, but go with it) and one at the University Medical TRAX station.