Why do Elixir maps have an update syntax but no insert syntax, meanwhile Erlang has both?

I frequently struggle to remember when to use which operator in the Erlang syntax. So my goal was to introduce syntax for the struct-like API (i.e. you expect the keys exist and you can only update them) and leave the dictionary-like API (adding and removing keys) in the Map module. So you can do Map.put/3 to add, Map.delete/2 and so on.