Abbreviated public subscriber counts are gradually rolling out starting next week. We heard a lot of feedback from the community following our announcement in May – we’ve updated our original post with more info here → https://yt.be/help/LF4J
They are most prob doing it to end like a subscriber war channels which got famous at the time like for example Pewdiepie vs T-Series and several more... But there could be more but that's just me xd