Late 4th Edition added bonuses to saves for some solo monsters, allowing them to roll saving throws at the start of their turn, or just automatically succeed. The reasoning being if the fight was only against the on monster, using control powers that hurt its action economy or limited its ability to act were overly potent. This continued in 5e, with Legendary Resistances, which allow some monsters to just auto-succeed on some saving throws.
These abilities are lame. They’re boring and uninteresting. It takes a character’s cool power that they’re spending resources to employ, and makes it ineffective. It wastes a character’s turn, making the player wait longer to do anything useful. And yet… they’re still better than the alternatives, both sides of the spectrum. Such as being able to stunlock the eff out of a big boss and wailing on it until it dies, or the MMO variant where big bosses are just immune to stunning and holds.