Logic of advertising POA (Price on application)?

What is the logic of advertising a house for sale with the price specified as POA (Price On Application)?
Until recently a handful of the houses in the area I'm looking were POA. This morning I notice that many more of them have been changed to POA, including one site!
Just wondering, thanks.

Presumably it's to avoid messers or they don't know what price to ask for. At the end of the day though, a property is only ever going to sell for what a purchaser is prepared to pay.