Key point is what David raised: Comparing speed with your partners on the uphills ... (versus safety - enjoyment - and comparing - on the downhills).
Any tour in Europe can be done with heavier skis + bindings, if start early enough and go slow enough. I even climbed Mont Blanc starting from the valley floor in Chamonix on Fritschi Diamir bindings and old not-light Tua Crossride skis. (It astonishes me how slowly lots of parties climb, who successfully finish the Chamonix-Zermatt HR.)
But if it bothers you that you might have trouble keeping up with your chosen partners, then lighter skis + bindings might be for you. Now it’s likely that even if you’re not “bothered”, you’ll still push harder unconsciously to “keep up”, so could get to the top with muscles more tired than if you had (rationally) maintained a slower pace. But note that the key leg muscle groups for skiing down (knee extension + hip extension) are different (opposite) from the key muscle groups (hip flexion + knee flexion) for specific lifting of the weight of skis + bindings going up.
i.e. if your “quads” are tired at the top of the climb, it’s not mainly from the weight of bindings + skis, but from all the stuff in your pack (since that’s what the knee extension muscles are lifting).
I’ve found that I’m fast enough climbing on my Fritschi Diamirs to more or less keep up with partners living year-round in France. So what matters more to me is feeling safer on downhills (esp steep icy slopes) which my French partners get me out on in springtime, and having fun skiing in tracked-up snow and crud and crust (which appears on the majority of days in Europe nowadays).
So when I needed to replace my skis last April, I got a newer pair of Fritschi bindings and had them mounted on a slightly heavier pair of skis (with an extra titanium top-sheet or something).
Note that if you ski uphill lots, or live in an area with steep hills or stairways (as I do) where you can train a lot pre-season climbing with extra weight on your feet or ankles, then the specific muscles will develop speed + endurance, and heavier skis aren’t going to be a critical factor out on a tour.
But if all your pre-season fitness was with trainers on your feet, then on holiday you suddenly load skis + bindings on your feet, well that’s going to have a noticeable impact on climbing speed.
On the other hand if you haven’t practiced for several months re-attaching your tricky lightweight binding on a steep slope, and you’re fiddling with that while your buddies in their easy-to-use bindings are continuing up the hill, then you haven’t gained.
Ken
P.S. I prefer to tour with people who are slow + steady climbing up, and then can reliably handle a wide variety of snow conditions getting down. Because the slowness going up is predictable and managable: I can use my energy to break an easier track, or climb ahead or off to the side to ski an extra run, and we still meet at the top.
But when the weather is closing in and we’re retreating, I don’t want to suddenly find out that my partner is falling on one turn out of four because they can’t make their light skis work in crud snow. Or their binding doesn’t release and they sprain their knee and now instead of being back warm in my car, I’m still out in wind + wet in a rescue.
