Mucel said..
And how people who practice both permanently decide what to do every day? Which days are dedicated to winging and which ones to windfoiling?
Is it only until they get a good skill on winging?
Is it a mess of gear or possible with only one balanced board? In this second case there must be performance sacrifices in one or both sports
I don't know of anyone else that wind & wing foils in my local area...I'm pretty much the redheaded step child

Anything under 15 knots and I will wind foil, if around15-20 I will probably wing foil because I love getting airtime...when the winds is 25+ I will choose depending on wind direction and launch site.
I see wingers struggle in cross off winds in waves but for wind foiling I can use the sail efficiency to stay up in the pocket and ride swells for miles, if the wind is cross shore and small swell, I can get super boosting air on a wing.
I have really worked on getting my gear as simple as possible:
Windfoiling - one board, 2 sails, 1 mast and boom with the phantasm 92cm mast, 926 and 730 front wings
Wingfoiling - one board, 2 wings with the phantasm 82cm mast, 926 and 730 front wings
Sometimes if I have a late work meeting and its already close to 6pm by the time I get to the beach, if the foil is bolted on the board, it takes 60 seconds to pump a wing, no harness, just climb into the speedos and you can literally be on the water as soon as possible to catch that last bit of wind, this has been a session saver a few times.
I honestly love both of them, each session is a learning curve or trying something new and having a combination of gear just means I can pretty guarantee a great time on the water.