I have been trying to figure out what the benefit of the Electronic Shutter might be. The advertised 30 fps sounds blazing fast. But I am hearing negatives about the way electronic shutters work.

It is my understanding that you get the rolling shutter effect when using the Electronic Shutter on moving objects, to the point of warped items in the picture.

The major reason I would want more fps would be for moving action, it sounds like I would be stuck with 12fps for the Mechanical Shutter which is the same as R5.

I found this information:

CONS of electronic shutter

  • Not suitable for fast-moving subjects
  • Distortion of subjects
  • Banding under artificial light
  • Cannot use flash

Here is a bit more from the same site:

When to use
An electronic shutter can be beneficial in the right circumstances, particularly when you need the camera to be silent in operation.
However, whilst a wedding or a golf tournament might seem like obvious places for silent operation, the movement of a golf club swing or the artificial lights at an indoors wedding in fact make both unsuitable for using the electronic shutter feature.
And even though an electronic shutter may offer super-fast shutter speeds, this really is negated by the fact that subjects for which you might need fast shutter speeds such as fast-moving action are completely unsuitable for shooting with the electronic shutter mode.
So, in fact, its usage is limited really to situations where the vibrations of a mechanical shutter are a problem, such as macro photography. And, with cameras such as the EOS R5 with its 45MP sensor any small amount of movement will show with such a high resolution sensor.
In conclusion, electronic shutters have their uses, but cannot currently replace the mechanical shutter.