> Once you have written it once, repeating the motion doesn't help you memorize it because it's in your short term memory. Memory research has shown that it's more efficient to review information when some time has passed.

Memory research has shown that if you have a fixed number of repetitions and want to maximize recall in the long term, spacing practice out over time is better than massed practice once at the beginning but that same research also shows that if you have a fixed time interval, more repetitions are better than fewer. (The recall curve for massed practice starts higher but drops faster than spaced repetition.)

Making children write the same character ten times is about making sure they'll still remember next lesson, not so much about making them remember for years. The long-term part is handled by implicit spaced repetition due to occasional exposure in assigned texts and their own reading for entertainment.

For learning a foreign language, explicit spaced repetition is more necessary, because learners are rarely exposed to enough content to benefit from the implicit spaced repetition effect.