Not all experience is created equal. Some types of project experience count as being more relevant than others simply because employers place a higher value on them. Here is why:
Getting experience in areas that require innovation or cutting edge skills for example counts more because that is where a lot of money is being spent and where there is more exposure or risk!
Employers hire those with experience in the types of projects they are financially vested in, so they can increase their chances of success or mitigate risk, makes sense right?