What is Hibernate TransactionStatus.canRollback used for?

What is Hibernate TransactionStatus::canRollback used for?

Even if canRollback returns false, the user can still attempt to rollback. (The attempt will fail, but nothing bad will happen.)

So why bother to check before rolling back?

I read the javadoc, but wasn't able to use it to answer this question. In the source code, I see that JPA compliance dictates throwing an IllegalStateException if Transaction::rollback is called on a non-active transaction. Is that the only reason?