The counties fund probation, so procedures will differ by county.
In L.A., formal probation is ordered on all felony probation cases- ergo supervised.
Most misdemeanor cases are informal, unsupervised (except by the court) probations.
In special cases, such as child annoyance/lewd conduct/molestation which is a
misdemeanor, can be sent for supervision by Probation.
Probation's budget has been severely curtailed; they no longer supervise DEJ - they've turned it over to the courts to supervise.
PS: a violation will still result in speedy VOP charges, whether supervision is formal (supervised) or informal (unsupervised).
Prosecutors who receive new charges normally check the rap sheet for active Probation cases & prosecute the VOP & trial at the same time. Any plea bargain takes into consideration the VOP.