Right now, reference sets are always stored only based on their internal object id.
If I'm in a microflow, I would like to sort my list, set it on the referenceset and have it keep that sorting in grids filled with that refset via association.
Especially with non-persistent objects this would be great, as the only real alternative for this is to use a microflow datasource, which makes for slower page loads and pop-in.
Even with persistent objects this can get messy. Having to build a new entity in between just to record a Sorting attribute creates a lot of overhead. Needs a 'Get or create' functionality, ensure these objects exist at the right places, manage security, delete behavior etc.
And it doesn't stop there, the displaying of this data is way more work too. All grids will have to show this specific Sorting entity, as sorting cannot be a one-deep referenced attribute. Not to mention any New/Edit screens would have to be crammed in between the two original entities everywhere.
All of this, simply because Reference Sets ignore the sorting.