“Dayan Fisher ZT”L, ?????? ?????, was not eligible to pasken the question about smoking.”
This is a very interesting suggestion, that a posek disqualifies himself from an issue because of his intimate association with it. In other words, his negius is posel. After all, considering that the Dayan zt”l could not stop smoking, how could he possibly have determined the halachah objectively? He inevitably would be matir.
On the other hand, if that posek is bringing proofs or support for his opinion, those proofs must be dealt with like in any other halachic discussion if one is to disagree. The negius may exist but becomes irrelevant.
I call this one a tossup. That said, the whole issue of halachically prohibiting smoking is irrelevant. Most people don’t smoke because society has determined that it is a disgusting habit (I agree). And people who do stop, don’t do so because of an issur.