The reason the characters stand on poles mostly have to do with the scene being either dramatic or to make the scene look "cool".
This trope is known as "I Have the High Ground":
Supernatural, magical, or just plain awesome beings know there's no better place to be effortlessly standing on than tall and usually thin objects, be they pine trees, lampposts or the nearest available tall building. This is flying for people who cannot fly. Or even the ones who can.
Less about true strategy and more about looking cool. Expect Dramatic Wind (actually, wind speed increases with altitude, so wind that seems dramatic to those on the ground is ''normal'' at high altitude). In anime and manga this has become a choice dramatic entrance for villains, introduced via a panning away of the camera from a completely every day scene (see example 1), or the aftermath of a dramatic event, to reveal that said villain was watching all along, and provide a nice segue for the next part. Example
As is mentioned on the page:
Hence, there is no particular show which sparked the pole standing, but rather its gradual adaptation into the anime world taken from real life Martial Art practice techniques, which became ever so popular and a regular occurrence because animation tends to increase the dramatic effect and make it scenic as compared to shows/movies, where the characters would (probably) look weird rather than cool, unless it's directly related to Martial Arts.