In gliders, engine failure is running out of lift (or failure to find and make use of same
) If too far away from the home field, you will be landing elsewhere. You get used to begging for lift while low within reach of a selected field, and if lucky enough to get away may repeat the situation.
A field landing in a glider with a sink rate of 200' / min is a considerably more leisurely affair than in a single engine airplane that is going down at 800' / min.
I suggest that sink rate and the ability to control it with spoilers, sideslip and flaps counts for more than raw glide ratio; however the glide ratio does give you more choice of fields.
The more difficult form of engine failure for gliders is engine failure of the towplane at low level where you have to let go of the rope and miss the towplane, but a student on first solo just managed it:
Student Pilot Makes Safe Landing 