I think it is very relevant. I think that because I have the experience, competence, and intelligence to make that determination. that is why I bothered to recommend it.
in my experience, SQDIFF is the only appropriate mode when the situation is characterized by exact color values and areas of zero variance. the other modes (CCORR, CCOEFF) are hard to predict because of their more complex calculations.
aside from that, all the “normed” modes involve a division (see docs). if that term happens to be zero for some reason, you get inf/nan. that happens when the needle or haystack are exactly black in a particular area. “normed” modes sound convenient but they really aren’t.
I have had to deal with modes other than SQDIFF often enough. they are always a headache. they are invalid options in many cases. invalid in the way that drinking beer with a fork is invalid. I say this because too often people have been of the opinion that if they just try hard enough, they’ll manage to drink that beer with a fork. any nicer way to put this has in the past frequently not gotten the point across.