I think that is because this thread is about general ski touring. As you mentioned, climbing snow shoes are a very route- and condition-specific tool. Their use also means you are in high risk/consequence avalanche terrain (steep, soft snow, narrow).None of you mention carrying verts, which i think are essential if you're climbing a couloir, either in powder or spring snow, where you're sinking in over a foot.
So far, the replies have been about things that (almost) everyone takes with them (almost) every time. The sort of ‘basic backpack contents’, that you can add to as the situation dictates. Climbing snowshoes are not part of that for anyone I would think.
There are many other items that MIGHT be needed too. Ski crampons would be the first thing to come to mind.
PS, I love your pics/reports of all the gorgeous couloirs you ski!