I found another very useful aspect of a simple speedline today, in a windstorm.
I go up cutting every lateral off as fast as I can to reduce windsail, but halfway up, the wind wants to take every lateral onto the bldg's roof, so I start hinging and pushing away from the roof. But with the twenty foot head left, even a lowering line would have still landed it on the roof in that wind. Right as the tree service owner I was subbing for yelled at me to come down because the tree's roots were snapping, I secured my trueblue climbing line at 2/3rds up, told the owner to take a few wraps on an upwind pine behind me, and zipped the rest of the tree in one piece away from the lean over the bldg, landing the head next to it, and then relaxing as I chunked the 30 foot single trunk down onto the brush.
Had I tried to catch that head using a lowering line, the chances are very good that both the tree and I would have gone over onto the roof!
Another nifty aspect of strategic speedlining in extreme weather.
Speedlines save lives and time!
jomoco