I would put money that they do both, active chase pursuit as well as opportunistic dispatch of prey.
I think your question related to speed noted in reports and not so in videos, I would say that it is already within a filtered context. The Sasquatches that are most likely to be caught on film would be the ones that chose to respond in a slow and controlled fashion. I think it is also worth considering that many of these sightings where the animal is observed advancing on prey or navigating terrain at a high rate of speed is more of a planned response by the Sasquatch. If a person walks up on an unaware or distracted Sasquatch we most often see this slow or controlled exit that is almost trying find the path of least or most resistance while tracking the behavior of the human threat. Many of the reports noting speed also seem to indicate that the creature knew of the humans presence a fair amount of time before the person knew the Sasquatch was there.
The Georgia dash-camera video is very interesting to me as the subject does appear to clear pavement in about 3 strides at a fairly high rate of speed with very little displayed effort.
In 2009 I witnessed a young male Sasquatch carrying a dead fawn at about 120 feet, after several moments of both of us locking eyes the creature deliberately dropped the fawn and u-turned into the willow brush ripping up and mangling vegetation during his exit, he was putting on a display. I and my family returned just 30 or so minutes later, we found several tracks, brush damage and examined the remains of fawn. The skull of the fawn had a single laceration just above the eye sockets ( about an inch behind toward the brain case ), beyond the surface damage to the skin we also noted that the skull actually had been crushed bluntly with some kind of object as the area of impact was now depressed, you could press with your fingers on this area and it was spongy and soft.
Since 2009 I have chased Sasquatch on 2 separate occasions, in 2012 and in 2014 ( I am was pretty fast around this time ) and in both cases the thing was easily 3 times faster than myself. The encounter in 2014 I managed to run 30 feet over and charge down a 20 foot bank and another 15 feet to the waters edge of the river and in that time the animal had ran out of a cedar patch about 15 yards across and clear a 100 yard section of field to the right on the other side of the river where it stood and began whooping again. The event from 2012 is somewhere here recorded on the forum but in short I heard it " talking " so I charged into the poplar and young oak thicket camera in hand ( it was around 35 yards deep or so ), about 3 seconds after I charged in I could hear it plowing through the thicket away from me, it sounded like a train derailing into the forest. The thing managed to cross the thicket ( about 100 yards long ) about 90 degrees of my nose to the right, it exited the thicket and hit the swamp flats ( I could hear the water crashing and spraying ) that are about another 30 yards deep before it gives way to large cedars. I only made it in about 20 yards in before I heard it break water. By the time I got to the waters edge by the swamp the water had settled down, I stood there a few moments listening. After some time I decided to either do a couple hand knocks or a whoop ( foggy on this part ) and in response a huge dead tree came crashing down just into the cedars, I turned back toward the road and thought " Ok idiot, time to leave ".
Reflecting on these incredible experiences, I can't help but laugh when I hear folks suggest that these things are not as powerful or fast as stated in reports, for me there is no question that they are well suited to run down prey.