Implementing direction of a 1:n relation with entity-reference Consider two content types A and B which are in a 1:n relation (say any A entity will be referenced by n entities of type B).
Implementing such a relation with entity-reference fields can be done in 2 ways:


content type A holds the relations:

CT A has its own fields plus one multi-value entity-reference type filed that will store the references to all the B type entities
CT B has only its own fields

content type B holds the relations:

CT A has only its own fields
CT B has its own fields plus one single-value entity-reference type field that will store the reference of each B entity to its own
parent A type entity.



With the first implementation (A type with a multi-value field) I give the user the possibility to sort the related entities, which is not possible with the second implementation.

Is there anything, on the contrary, that is possible to realize with the second implementation but not possible with the first one?
Your claim that "With the first implementation (A type with a multi-value field) I give the user the possibility to sort the related entities, which is not possible with the second implementation." is false.

Some things may be easier one way. Other things may be easier the other way. But ultimately, with Views you should be able to accomplish pretty much anything with both of these approaches. So use the one that's natural for your data.