Pex has been used in europe for decades in both domestic h&c water & heating applications.
It's not the just the future, it's the now. most new homes are being built with it. The cost of
copper being through the roof combined with the cost & ease of installing the pex make it an easy choice for most.
The last house I built & sold I used all type L copper, just because I didn't want call backs, you can imagine the added cost. Now I'm using only Pex.
Now if I can only find an alternative to copper for electric wire...