Athletes, artists, entrepreneurs say "this has been my dream" all the time when achieving something superlative. But you qualified with "necessarily" so I guess technically you're correct, but it would be kinda' weird if someone told me that "X is their dream" and never did anything about it, especially if it's relatively achievable (i.e. not "going to Mars" or something).
Getting decent at snowboarding isn't some crazy goal (and you need to be decent before you're good, or great). I started skiing late in life and I try to go a few times a season to keep up with it. I'm by no means good, but slowly getting better.
Why would it be weird? My grandmother dreamed of being a school teacher, never did it, and talked about it until she died. The closest she ever got was teaching Sunday School for a few months.
It's common to have a dream and do nothing concrete about it. That's part of why we call it a dream. Sometimes it's less about the thing itself and more about the unfulfilled and unrealistic expectation.