And it doesn't have to always mean a complete ban. For example, my wife's game has a character who has the ability to launch an attack while Insubstantial. She let the player buy it, but told them that they'd have to be somewhat sub-PL with the attack to make up for the ability to do that. That's meant that while its an advantage, its not overwhelming.
The biggest thing, as I harp on, is being mindful of how the pieces interact, and knowing to watch for them.
As I've noted when talking about my wife's old character Dupe, Duplication wasn't overpowered intrinsically; neither was high end Charisma and skill; even the old 2e Distract feat, though it was borderline, wasn't. But put the three of them on one character and it was a huge potential problem.