I can say from character experience in experimenting with this about a year ago. It really is not a BAD approach to working. Take for example POV arms (first person arms) for a shooter. You could definitely have a fully uniformed/clothed arm and have it decimated for sure. Though you might wonder where do we draw the line…
I'd say that it depends of the purpose of the object. Most of static meshes with organic/fluid contour (such as sculpted hair styles, rocks, trees, etc) will look just fine with decimation master. On the other hand, once you want to animate or even slightly deform your low poly, go the regular way. As for your example, I'd…