I've understood it as an option to feel who called you. That would make a big difference for me. If I feel the name and that name is my wife's, I'd probably excuse myself a minute later and call back. If it's an incomprehensible vibration, it's someone I don't know or who calls rarely. That type of call can wait.

Also, your suggestion can be combined with his. Distinctive vibration for the name + urgent/normal as a second vibe.