Idk, I think it's extremely statistically rare coincidence for nominative typing to be a better default than structural. In other words, it's much more useful (by default) to have some function work on more types than be a little bit more type-safe for the exactly the type author had in mind when writing it. In my opinion, type-safety has diminishing returns and the most of its usefulness lies in trivial things, like passing a string instead of some object or array just as a typo, or writing a wrong field name when mapping one object to another, but nominative typing lies way beyond my imaginary line marking the zone when types become more of annoyance than help.