It’s evidence that supports vegan causes. A tool for the vegan activist’s toolbox. In particular, environmental vegans benefit when the highest climate footprint animal (cows) are shown to have intelligence. Intelligence is a factor in assessing animal welfare and suffering. That is why it is posted in c/vegan.

(edit) note as well that when dealing with vegan-hostile meat eaters, this is the kind of story that you can present without attaching politics to it. Just show them and say “isn't it cool that this cow figured out how to scratch her back”, and leave it there. There’s nothing controversial about that. It just drops it into their mind that there is some intelligence they did not know about. Let them realise for themselves what it implies.