From Schoeps' Web site: "The B 1 ... is especially suitable for protecting a capsule from rosin dust when attached to a string instrument (e.g. with the VA 1 violin mount) and as a hygiene protection."
The "B" in its product designation stands for "Besprechungsschutz" ("Schutz" = protection, "Besprechung" = being spoken into / at). Schoeps' actual windscreens all have product names starting with "W" ("Windschutz").
Is it better than nothing when there's wind or air conditioning? Yes, but not by much; you're playing the odds that there will be only very minimal, gentle air currents, just at the margin of what the microphone's built-in screening could have handled anyway. Also, a "Besprechungsschutz" generally is designed to protect the capsule from moving air that strikes it more or less on-axis. Wind currents don't respect that assumption, though.
--best regards