The broad-edged pen, and what it still teaches
Nearly every serif on your screen is a frozen record of a flat nib held at an angle.
Pick up a broad-edged pen, hold it at thirty degrees, and write an o. The stroke is thick on the down-left and thin on the up-right, and you did nothing to make it so: the nib is a flat edge, and the width of the mark is simply how much of that edge is facing the direction you are travelling.
That single fact explains most of what a serif typeface looks like. The thick and thin of a Garamond, the axis its round letters lean on, the way the join between bowl and stem thins to nothing — none of it is decoration. It is a record of a tool.
The angle is the style
Hold the pen flatter and the contrast moves: you get the upright, heavy-footed look of an uncial. Hold it steeper and you approach the diagonal stress of an italic. Change nothing but the angle and the letterform changes family.
This is why type designers still learn to write with a pen even though nobody sets books with one. The pen teaches which parts of a letter are structural and which are habit.
What the pen cannot teach
It cannot teach spacing. A calligrapher spaces by feel, one letter at a time, and every line is different. A typeface has to space every possible pair in advance, forever, without knowing what will sit next to what.
That is the jump from writing to type, and it is a much larger jump than drawing the letters.