For me it is just anouther training tool. One that is good to know how to do and use correctly.
Definitely agree with this.
Oh and when my reiner is really high and I need to trot her down generally I posted ... less effort than trying to sit her bouncy stride =P
When I ride my all around horse, if I'm working on the english I'll still ride in a western saddle when I school. So I'll post then too.