I am not a Google Workspace user but I hear that its features actually lag behind the personal accounts?
I have seen the rationale that Workspace is intended as a workplace solution, the accounts would be managed/controlled by the Workspace administrators, and allowing this features could allow Workspace administrators access to potentially sensitive data. (For example, see https://support.google.com/a/thread/221999832/can-t-join-fam...) And indeed, I wouldn't necessarily want an employer or its IT department to have these by using an employer-provided Workspace account for them.
But this also means someone who is using Workspace for an individual or a family to get other Workspace features (custom domain email, storage, etc.) is blocked from using the same account for those features - so ends up needing a consumer-level Gmail account as well.