https://www.ralfgroeseldesign.com/blog/tube-vs-softkite-an-epic-battle
Et pour ceux qui n'ont pas le temps de lire le blog au complet, "the winner is" :
CONCLUSION
As you have seen, both concepts vary a lot but it’s the Tube-kite that stands victorious.
From a designers point of view, it shines in every aspect and its simplicity in design is the key to controlling its complexity. Tube-kites rule most of the sport related requirements, although a high aspect race Soft-kite does have performance advantages when it comes to its ability to run upwind in ultra light wind conditions.
Soft-kites have an approximate market share of 4%, meaning that 96% of all kites sold worldwide are Tube-kites. This figure basically validates the success of the concept. But YES, even though the production cost is very high, Soft-kites do have an right of existence for niche applications, especially in light wind race conditions on a foil board.. Without being too sarcastic, you have to be an believer to think that Soft-kites are the future of the entire kite market with all its facets.