You can take a peek at the internal structure by using IO.inspect/2 and it’s option structs:

iex(7)> NaiveDateTime.utc_now() |> IO.inspect(structs: false)
%{
  __struct__: NaiveDateTime,
  calendar: Calendar.ISO,
  day: 17,
  hour: 12,
  microsecond: {614456, 6},
  minute: 37,
  month: 9,
  second: 47,
  year: 2019
}

That’s how all structs work in Elixir.

Structural comparison of dates was actually used as an example of the new type system when it was introduced! At the moment I don’t believe it can catch this within a function like Enum.min_by() (obviously since it didn’t for you), but there are more type system changes coming in 1.19 and 1.20 which have to do with functions, so perhaps it will eventually?

Yes: CompareChain — compare_chain v0.6.0

The OP would be:

import CompareChain

datetime1 = ~N[2019-09-26 01:00:00.000000]
datetime2 = ~N[2020-01-24 00:00:00.000000]
compare?(datetime1 > datetime2, NaiveDateTime) #=> false