elem/2 is guard safe, I think thats the main reason why it is in Kernel.

put_elem is probably in Kernel to line up with put_in/2/3, but I’d like to not see it there as it involves the cost of copying the full tuple.

Tuple.append/2 is probably in its very own module, because it involves the cost of copying should be carefully thought upon before just using it.

These are assumptions based on observations mixed with a bit of personal opinion.

In my view using functions on tuples feels wrong (but there are always exceptions). They seem like intrinsic “values/units” that are constructed with the tuple notation and smashed with destructuring (via pattern-matching).

Strangely with maps I’m quite the opposite - they seem more complex and free form than tuples so I tend towards using functions rather than (yet another) map notation (I guess Clojure made me operator averse/function friendly). I keep having to remind myself:

• that I can pattern match on maps
• and that with map pattern matching ignoring parts is implicit

List are in the middle. I have to be backed into a corner before I use hd/1 or tl/1 preferring the cons notation - probably because that is the bread and butter for pattern matching (for destructuring) - otherwise they are dominated by higher order functions (… and Enum.at/3 makes me cringe).