@kl005 is correct. Sous vide lets you control the temperature so that it will be hot enough to break down pectin, while not so hot as to burst the cell walls (which happens when you boil the vegetables). The higher temperature is needed to break down and dissolve the pectin in the vegetables - which won’t happen at a temp of 50 Celsius.
Please correct me if I’m wrong everybody. I’m still pretty new around here…but I’ve been researching quite a bit and I think what I’ve said above is correct. (I’ve taken the advice of @chatnoir …“Do the work!” 
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