I also see lots of cars on the way into seattle every day who are leaving what would have been absurd distances in manual driving constantly. These all seem to be auto-driven. This latter definitely makes my life easier getting through traffic as there are so many 200ft+ gaps now at 20 mph on the freeway.
The companies making the software of course want to avoid lawsuits so they're going to ignore time savings.
Also get off my lawn.
Often, when I'm following a 1st car, and this 1st car changes to another lane - and there's a 2nd car ahead that the 1st car was following - I'll swap from the Short distance to the Long distance. This keeps me the same distance behind the 2nd car as I was when the 1st car was between us. Sometimes a 3rd car will swing in between me and the 2nd car - taking the place of the 1st car - and so I cycle through the distances back to Short. Like holding open a space, because a driver more aggressive than me will force their way into the gap anyway.
Other times, I'll use the Medium distance in bad weather, or on empty highways so I'm not pressuring the driver that I'm following.
From the manual: Select a distance from the table below. Note that the distances shown correspond to a vehicle speed of 50 mph (80 km/h). Vehicle-to-vehicle distance increases/decreases in accordance with vehicle speed.
Long ~160 feet
Medium ~130 feet
Short ~100 feet
(160 feet ought to be enough for anybody - almost every modern car and truck has a 60mph to 0mph braking distance under 160 feet on dry pavement. This car's braking distance is 125 feet, so Medium follow distance keeps you far enough behind a car that you could stop entirely in the gap.)