Not disagreeing with you, but it's worth noting that tuples support random O(n) access by index. They can therefore be used in place of arrays for some simple applications.
https://www.erlang.org/doc/system/system_limits
There is also some hope that future versions of the Erlang compiler will allow mutable O(1) update of tuple elements through setelement (code inside a process is - almost - guaranteed not to have shared references).
Safe destructive update of tuples has been implemented
in the compiler and runtime system. This allows the VM to
update tuples in-place when it is safe to do so, thus
improving performance by doing less copying but also by
producing less garbage.
It should be possible to add Elixir syntactic sugar to make this more concise and natural.
O(1) for reading I believe. The slightly awkward array module is built on top of tuples, a 10-tree of tuples? or something like it.
But good point, once in a while I see list_to_tuple to provide faster indexed reads on lists.