Haha. Well, in my experience, motorcycles and cigarettes have much the same issues. While I think that cars are very over-used, there is no denying that they are *much* safer than motorcycles. Realistically, in the western world, riding a motorcycle is a lifestyle choice that reflects an acceptance of significant risk in exchange for a desirable experience. In fact, this almost exactly the (superficial) reason for smoking. No one can credibly claim that smoking is not harmful, yet people do it all the time. Why is this so? I don't know the answer, but I am sure the basic reasons are very much the same as riding a motorcycle - "because I want to."
Asking or expecting someone to quit smoking when they are in hospital for smoking related disease is basically the same as advising a motorcycle rider with a shattered leg to stop riding. "It's a bit late for that advice Doc."
And I absolutely would re-attach the fingers of someone who intentionally cut them off - and if they tell me they are going to do it again, then I will re-attach them again (if possible, the second time it's doubtful to be successful). That person would also see mental health professionals prior to going home. And I would not consider it a waste of time or effort. For one, how am I supposed to know who is really going to cut off their fingers again, and who is going to 'get their life back on track'. Or even never get their life back on track, but create some kind of artistic or engineering masterpiece? Would you want your doctor to make that decision for you? What if you were bereaved/drunk/depressed?
Virtually all doctors (and indeed almost all people) take a rather more nuanced view of so-called self-destructive behaviours. I believe that if we were not having this conversation on a forum that you would also have a more 'holistic' view of the factors that cause people to make the choices they do.
Sometimes it's important to help people just because they need it - it's a safer choice than trying to judge who is worthy.