I agree totally for those who have medium to large numbers of snakes. Or regarding certain projects (that double het animal isn't worth a whole lot without a matching partner). And for several more reasons than the ones you list. Snakes can get sick and die. Snakes can be missexed.
But for those of us dealing with smaller collections of snakes, holding back 2 genetically identical animals really limits the possibilities of what we can produce. So, in many cases, I'd rather be delayed in reaching a particular target morph because of one of these types of issues, than be unable to reach many other morphs I'd like to target because I just don't have the genetic diversity. One has to find a balance between the two.