Pole Dance actually requires a lot of strength, flexibilty and coordination.
You can differentiate between athletic pole (it's a mix of dancing and going gymnastics on a vertical pole) and exotic pole (sexy, slinky movements, you often wear high heels). But exotic pole dance is also really exhausting.
Actually neither of them is like lap dance.
In answer to your 'dirty or healthy' question my answer is
it is healthy in the athletic dance style and also in the exotic dancy style (as long as your teacher is good). Both build up muscle, you get better coordinating yourself, you work out. You get all the health benefits of regular sport, but (at least in my opinion) it is way more fun