Help with a clearance (Aussie)

[Cougar]

G'day all,
Got this clearance today (in Australia) and am a little confused. I am hoping an Aussie ATCO can help. Was passing FL130 on descent and had traffic 10 miles away co-level, which we had sighted. We were descending OCTA and ATC told us to "leave control area on descent, visual".
Does this mean you must remain visual on descent, ie clear of cloud etc, or does it mean you are responsible for your own visual terrain clearance. Why would he give us this clearance?

Look forward to someone clearing this up for me.

Cheers

[89 steps to heaven]

Hi Cougar

Basically yes to both. If the LSALT for the route is high enough to be in CTA, the controller has to give you a clearance to leave on descent that takes this into account.

If an IFR let down was required, the sector entry and begining of the procedure can be in CTA and have completely different tracking requirements, and clearance, to a visual descent.