As a BMWCCA and PCA instructor, I certainly encourage those who think they might like to try driving on a track to do so. It is a ton of fun and will definitely teach you about your car and make you a better driver. That said, I certainly would not berate anyone who chooses not to track their M3 - to each their own (even though you are kind of missing out
The biggest counterpoint to tracking IMO is that many insurance companies will not cover an accident on a race track, even if it is an educational event and not a competitive driving event. Of course this varies, but I think it makes sense to be aware of this. Accidents do happen occasionally on both track and street and on the street you are guaranteed insurance will cover it.
Likelihood of damage also varies widely depending on track design. Someone mentioned Watkins Glen and that is a very unforgiving track with Armco everywhere. In contrast, Mid Ohio (my home track now) has very good run off areas and only a few places to smack into hard objects.
On a related note, if anyone in the greater Ohio area is on the fence and would like to check it out, let me know, I'd be glad to take you out on track (in my car) next season to give you a taste.