realskiers

Not sure you need to bend a ski in Pow but the sidecut helps the ski turn. If you just ride the sidecut there is a big difference between a 15m and a 30m TR. As well most turns in pow are brushed carved turns and the bend that one gets on hard snow, pressuring the tips in an edge locked carved arc is not happening. But again sidecut and TR is key to doing slalom brsuhed carved turns in soft snow.

The softness of a ski is a factor in float. the more the skis bends at the waist the higher the tips come up. But also the deeper one sinks from ski bend the more one has to flex to release the skis. So yes wider and softer helps float and potentially ease of use, but it is really width and speed that keeps a ski planing. . The faster you go the less need for soft and wide. What Max said is also a key point, too soft and you may get slightly better float but you will ge bounced and tossed in chop, crud and smaller bumps (that you can ski through with a stiffer ski). I also find that where soft skis really fail is when you get back on groomed terrain where they haven't groomed that day and you have a lot of harder chop. Soft skis just get tossed in this stuff and it is generally plentiful on powder days at most resorts (getting back to lifts).