Two serialization encoding for tuples

[greenhat]

We have two ways to encode tuples:

1. as Scala tuples (Coll[Any] 2+ items), see - https://github.com/ScorexFoundation/sigmastate-interpreter/blob/08627b714f04794b8f8cc785452aa8dc58bc9c48/sigmastate/src/main/scala/sigmastate/serialization/DataSerializer.scala#L126-L131

2. as Tuple, see https://github.com/ScorexFoundation/sigmastate-interpreter/blob/08627b714f04794b8f8cc785452aa8dc58bc9c48/sigmastate/src/main/scala/sigmastate/serialization/TupleSerializer.scala#L26-L35

I see the second option as more of an exception to parse existing on-chain register values. With the first option being a "default" way of encoding tuples. Is that the correct assumption?

Side note. With Tuple constrained to EvaluatedCollection, I don't see a way to have an arbitrary expression as an item in Tuple, which make both above options semantically equivalent to me. Am I missing something?