to be clear I wasn't saying Smart is useless just that smartctl doesn't always tell you every thing so you shouldn't rely as a definitive answer on all issues on all disks.
As for raid controllers well that's a very long conversation there are good reasons the enterprise ones do not, at least not directly in a way you can extract using the smartctl command instead they have more advanced checks available through the drivers and additional monitoring tools provided by the manufacturer of the raid controller.
as for the predictive nature of smart well that's actually in its specification it predicts errors based on indicators.