I used to think the same as you but... One instructors seminar later and having a look at quite a few threads on here.
In a very very few cases it may help, but the boffins in the know crunched the numbers and found that it kills more people training for it than it saves.
Just a look at the AIBB reports over the last 10 years shows that folk stalling/spinning it in on finals doesn't carry a heavy butchers bill.
Now coming in to fast and sliding off the side or off the end so I would say the problem is to much energy rather than not enough to remian in controlled flight.