Is there any precedence for that though? If I remember correctly, their point deduction happened because they faked their accounting report[1]. There is nothing related to their participation in the Super League. While it is not surprising if they get another form of punishment from the Seria A governing body, I believe forbidding them from participating in the next season is way more effective compared to a point deduction since the goal of that competition is simply to get more money. Juventus will still earn money if that does happen, although it seems unlikely given how fans vehemently oppose this new competition.
[1]
https://www.goal.com/en/news/why-juventus-have-been-docked-15-points-italian-football-federation/blt4776860c5347c3c2I know but I believe it is a reason on tip of iceberg and there is no coincidence for that investigation against Juventus. It happened after Super League seemed to come closely to activation day. It is also not coincidence that after got the serious punishment, Juventus announced that they left Super League.
They possibly realized that they will got more cost from participation in Super League plan before it succeeds and they can get profit from it. Potential cost is bigger than potential benefit so Juventus gave up.