I think most has explained why tubes are used on snow, when you do both water and snow.
When only on snow, I think I would use foils too so the pump is not needed.
And the foil rigging is much easier, true.
But I dont get the "have to break down" ? (why do so many think foils are easier to pack down ?)
A tubekite takes very very short time to pack fully down (onepump kites have no strut contra vents, so when you open the valves, it goes flat instantly, and no messing around with anything in the cold) - and you dont have to remove the lines here either if you dont want to !
In fact I've used a lot of time pressing air out of foils, when packing down - so I dont think it is faster, honestly - in some cases maybe slower in fact
I am talking about "water" foils though - as fully open cell foils would be VERY fast to deflate (but unusable on water...)
But still - it does not take long to de-rig a tube kite !
The bag is somewhat the same size for both types also - not much difference.
But rigging a foil is way simpler because you dont need the pump
Kindly, Peter Frank