Okay, so what you meant was not that you don't see a use case, but rather, you don't see why they implemented maps as a replacement to dict/orddict, and in lieu

Okay, so what you meant was not that you don't see a use case, but rather, you don't see why they implemented maps as a replacement to dict/orddict, and in lieu of frames. Those are different questions, the latter of which not one I feel capable of answering, given that I wasn't involved with the discussions. I assume the reason for wanting to replace dict/orddict is because they feel very much a second class citizen in the language (see at bottom for a comparison of why pattern matching trumps separate modules), dicts are inefficient for small collections, and orddicts are inefficient for anything but small collections. As to why they went this route instead of frames, I recall seeing it in the discussions (I believe the Erlang mailing list but I can't recall), but I never paid that much attention to it. But then, to the first, why not just keep the dict/orddict syntax, a completely frivolous example, solely created to demonstrate why pattern matching is cleaner then dict/orddict - %This just increments a map if the password passed in matches, sets the counter to one and the password to the passed in password if the map does not contain a password, and throws if the password does not match, but does exist. incrementAndGetIfAllowed(Map, Password) -> case Map of #{password := Password, count := Count} -> {Count + 1, Map#{count := Count +1}; #{password = _} -> throw(bad_password_can_not_increment); _ -> {1, Map#{count => 1, password => Password} end. %We have to extract first, then do our logic separately. Behaves the same as the prior function. incrementAndGetIfAllowed(OrdDict, Password) -> CachedPassword = orddict:find(password, OrdDict), CachedCount = orddict:find(count, OrdDict), case {CachedCount, CachedPassword} of {{ok, Count}, {ok, Password}} -> {Count + 1, orddict:store(count, Count + 1, OrdDict)}; {_, {ok, _}} -> throw(bad_password_can_not_increment); _ -> orddict:store(password, Password, orddict:store(count, Count + 1, OrdDict)) end. And that's just with a map/dict holding two things. If you have complicated logic based on the internals of the map/dict, it could remain pretty elegantly matched upon with the map, while getting exponentially uglier using a dict/orddict.