Not going to go into copper/plastic pipe + & - points, except to agree that copper pipe is often the harder thing to use. Can't see though why a plumber will do a easy job using push fit, when soldered or compression using copper will be also quick. That is the trouble with anything that saves, even a little time, tradesmen will use it everywhere. On a house recently, that was getting a complete new gas system & plumbing, the customer was told by his engineer that it had to be plastic pipes as copper could not be fitted upstairs. He was stunned when I informed him that I had already fitted the main pipes in copper for him!
Better to give the potential customer the option of copper or plastic, & let them decide if they want to pay extra. But I know a lot of prices out there for plastic jobs are actually dearer than what a copper install would be!