Why did the L1011's direct lift control help make good landings?
John's fine answer is correct, but there is a bit more to it:
When increasing lift by pulling on the yoke, in most airplanes the elevator moves trailing edge up, decreasing lift initially. To look at the process in detail:

The yoke is pulled, the elevator moves trailing edge up
Downforce on the horizontal tail is increased without any lift change on the wing, so total lift is diminished. The sink rate increases slightly.
The lift imbalance adds a pitching moment, so the nose of the airplane rises.
Now the angle of attack on the wing increases with the pitch angle and lift increases. Only now will the desired reduction of the descent rate kick in.

This effect is especially pronounced in flying wings, but it also is noticeable in regular airplanes. Now compare that with partially deflected spoilers:

The yoke is pulled, the spoilers close.
Lift increases without a change in the elevator angle or the angle of attack. The desired reduction of the descent rate is immediate.

The effectiveness of spoilers is limited, so this technique will not allow you to fly aerobatic maneuvers, but for landing it is perfect. Drag is increased, so the engines will have to produce a bit more thrust than with spoilers fully closed, giving you more immediate engine response, too.