The picture from Billiebob shows Altiport Courchevel in the french alps.
Jetblue, you have correctly noticed that the peculiarity of mountain airfields other than the short length of their runways, is their slope, and there is a reason for this.
There is no such thing as having to use brakes downhill and skid out of control. One always lands uphill, and takes off downhill.
When landing or taking off one is committed and there are no options available.
On take off there is no possibilty to abort, and on landing no possibility to go around.
Though the configuration of mountainous terrain involves slopes, mountain strips are intentionally always with a slope.
At those heights, with the reduced air density affecting lift and reduced power affecting engines in our typical underpowered a/c, a flat strip however long, would almost inevitably render take off impossible and result in a very long deceleration at landing.
The slope acts a secondary source of energy at take off accelerating downhill and does the opposite at landing uphill, gravity comes into play.
Mountain rating in my view is far from useless or "Crappy" it sharpen's one skills, deveops coordination and precise flying, then all trainers i've ever seen are tailwheels, with all the benefits involved..