Seeing we're discussing separation, Lizzi3v for 34 with a heavy on the arbey arrival also for 34. We get asked to reduce to 220, then 180 then back to min approach speed. It looks pretty tight, so we comply promptly and then get asked to sight the heavy on a 3 mile final. Ok, traffic sighted.
Then it comes..... Roger, maintain own separation, cleared visual approach, contact tower, ciaaaaao.
This instruction to maintain own separation doesn't actually give US any more track miles, in fact it can make things a royal PIA. Ontop of the approach, we're trying to shed energy, make a 'square turn on to final' and now trying to stay behind something that we're probably already too close to anyway. It can add a bit of workload at a busy time.
I have just presumed it changes your separation standard between arrivals, is this why it's done because it just seems to lob the separation back onto us.