For any sort of long term survival, the valves MUST rotate. This is not governed by the keeper type, that's simply a function of the valve material and the manufacturer/application.
The rotator seen commonly on Chevy motors are there to GUARANTEE rotation, that's why they show up in industrial motors. Without rotation, the valve is not able to wear concentrically. If you've ever wondered about why valves aren't square, this is part of it. Put dykem aka layout dye on the valve tips, run it for a bit, and check. They may not spin round and round but if they were supposed to run in a fixed axis with no freedom of rotation, they'd be keyed. They WILL rotate back and forth and over time make full rotations.
Rotators get tossed for weight, they maintain the same installed height on the spring. The valves rotary motion occurs simply because they aren't constrained.