simple-fella
https://grapheneos.social/@GrapheneOS/114146787766360796
Work profiles are not meant for personal use and most people are not meant to know about them. The Android community used them as a poor's man Private Space before they made that feature. Private Space and OEM features similar to it were likely at least partially inspired by how people were using work profiles via local management app.
Private Space is essentially just meant to be a nested user owned by another user.
In the future, support for having multiple Private Spaces would largely replace 1 person using multiple secondary users.
Android intended secondary users to be for actual separate people using the same device and work profiles to only be for Bring Your Own Device enterprise deployments where your work phone is nested inside your current phone and managed/owned by your work's device management system rather than by you.
Generally the idea is that it would be better to use Private Spaces (and potentially even the new terminal VM feature) instead. At the moment, further development would be needed to allow more extensive usage beyond the current single, Owner-only Private Space limit.
As for the other ROM, I imagine their feature is likely insecure and GOS devs would prefer their own secure implementations.