[QUESTION] 33% of storage efficiency.

[Rustbread]

Storing [1024 *1024] integer values as BsonArray takes 12 MB while it should take 4MB, and at worst case of 64 bit interpretation 8 MB.
So what is the deal here? There was no warning about the 33% storage efficiency.

There is nothing that suggest that smaller arrays are stored in more efficient way so it is flawed.

So is there a way to store it normally without the massive overhead?