Depends on the time you want the virtual shutter to be open. I agree with you it can get excessive if it gets too pronounced, but a long blur is also a visual indication a character jumped more than one line during the (virtual) screen refresh (virtual, because we want it to look consistent, regardless of refresh rate). It should also disappear before the characters settle into their grid.

I'm a cinema person, so, for me, 24 fps is the right framerate for everything.