I don't think that's correct. I have a MIDI keyboard. If I select note timings, it will play the pitches I select on the keyboard in the timing I select. This produces accurate notation. It also produces a useful version of the music which can be edited - change key, change timing, add parts, etc.

Other people may take a MIDI keyboard and play pieces directly into the computer. This process produces MIDI's which are only good for listening. John in Kansas referred to them as "stuttering," and that's a good term for their inaccurate timing.