You're on to something but I doubt it's the syllables. Rather it seems about phonetic ambiguity.
"twentynine" could mean both 29 and 2009, so it's better to use "twothousandandnine" for the latter. "twentyten" cannot be interpreted as 30, only as 2010.
Na, names are about pronunciation (how you call someone). Written letters are an approximation of that. You can't pronounce a newline, so there's that.