VFR terminology in Class B

Hello everyone.

Two months ago I flew VFR into Memphis. This was my first time landing at
the primary airport of a Class B. From about 30 miles out, the approach
controller was providing vectors and altitudes to maintain. I was told to
expect runway 27. About seven miles southeast of the airport I was told to
"descend at my discretion." I was not lined up with the runway at this
point, and was not sure if he meant I was just limited to descending or
should intercept the extended centerline. I asked him if I was "cleared for
the visual" and he replied that "cleared for the visual" was an IFR
clearance and I was not IFR. He repeated that I was cleared to "descend at
my discretion." I figured this meant line up and land on 27. I did that
and was handed off to the tower.

At most other towered airports I have been to, the controller always says
something like "enter a 3 mile base for 27" or "report a 3 mile final for
27" or something to that effect. I was expecting the same at Memphis. My
question is: Was the controller correct in this situation to use the phrase
"descend at your discretion."

Thanks for your thoughts.

Matt