400 Hz is used where weight is important because the magnetic cores can be smaller/lighter. This applies to transformers as well since a lower inductance (smaller core/number of turns) can be used than required by lower frequencies.
IIRC, the US Navy was using 800 Hz or higher at one time, but the "singing" from vibrations in the cores must have been very annoying.
In the early days there were eddy-current problems in the laminations of the magnetic stuctures of motors/transformers. This gets worse as frequency is increased. Improved magnetic materials helped a lot as did thinned laminations IIRC.
60 Hz, the North American household standard, allows slightly smaller components than 50 Hz, but the desire to suit world-wide markets has negated this in many cases.
And then there's 25 Hz. The early hydro plant at Niagara Falls was 25 Hz. This meant that a lot of New York state and Ontario lived on 25 Hz. Motors and transformers were BIG. Southern Ontario didn't switch to 60 Hz until afer WW2. I understand that the abrasive materials plant at the Falls still runs its furnaces from 25 Hz. Resistive heaters don't care about frequency.