Is this true? Granted I usually just deal with using a standard toothbrush when I go on vacation but I have absolutely put my electric shaver and electric tooth

Is this true? Granted I usually just deal with using a standard toothbrush when I go on vacation but I have absolutely put my electric shaver and electric toothbrush in my checked bag without issue. I thought there is now a battery size allowance that allows these to go under the plane.