It's definitely legal, we've used them since Ultimate Ascent. It can both be helpful and entertaining to see what you can with it. It was especially fun with Ultimate Ascent since our robot, Mater, was a dedicated climber robot.
Here's a video from our last match at GKC Regional using our GoPro. We lost this match, but I'm so proud of this robot and it's exciting to watch the climb go well every time:
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