Bathroom and kitchen: does wood belong there?
This question comes up often and deserves a straight answer. And the honest answer is: it depends less on the room and more on your window.
Wood is a natural material. It responds to moisture — that's not a flaw, it's the definition of it. The real issue isn't "bathroom" as a label, but what actually happens at your window: does it fog up in the morning and stay wet for hours? Is the blind a metre from the tub, in the splash zone? Or is it an aired bathroom with a window that opens, where condensation is gone in ten minutes?
In that second situation, wood lives well. Kitchens likewise: steam from a pot isn't a morning shower, and a working extractor hood settles most of the debate. What I'd avoid without a second thought: mounting the blind where water reaches the slats directly. That's not a matter of quality, it's a matter of common sense towards the material.
Two habits that make the difference anywhere: air the room after a shower or after cooking, and wipe the condensation off the frame when you see it — not for the blind's sake, but because a window that "weeps" daily is a problem in itself, blind or no blind.
And if your window really does stay wet? Then I'll say it plainly: don't force wood in there. Better a window without a blind than a blind that suffers. For every other window in the house — and there are many — wood remains the warmest choice there is.