We considered it when we moved but we couldn’t make it work financially. The developer needs to get their money somehow so you either end up paying way over the odds for the new house or they give you a rubbish px price on your current house. Sometimes both.
Most people who PX have a house that wont sell for some reason or another, this adds risk for the developer so the price needs to reflect this.
One of the biggest issues for me was that it limited us to a new build and these are generally small, on an estate with lots of close neighbours, small gardens, expensive and often go into negative equity shortly after buying due to it not being new anymore and there being lots of the same house available. I realise there are lots of sweeping statements here and new houses will work for some, its just my opinion and findings.
We ended up significantly lowering our asking price and selling the conventional way and were still better off.