In a presentation, I assign the effect "Appear" (on click) to a paragraph of
text. Using Effect Options, I assign "Letter by letter" to text animation.
When shown, the letters still appears all at once. I say "appears", since
there's a very small flickering that could indicate that the letters are shown
individually, but much, much too fast.

While trying to slow down the effect, I noticed that the "Delay between
characters" is expressed in percent, which is a quite meaningless unit. It is
also limited to 102.4%. Milliseconds would be a better unit. The "Speed" setting
under "Timing" is disabled.

Although many effects are just intended to lighten up a presentation, the
"Letter by letter" is important since it is the only choice to represent user
input via the keyboard.