In other words, you can wind PEX throughout the walls and floors with a continuous, uninterrupted pipe to its final connection.
PEX conserves energy by reducing heat transfer, or loss of heat through the pipe wall. By contrast, metal pipes are particularly prone to heat loss. PEX also doesn't corrode—another advantage over metal pipe especially galvanized steel pipe, which consistently corrodes over time. Compared to copper, PEX is more resistant to scale buildup and the resulting loss of flow through the pipe. Also, PEX is much less expensive than copper pipe.
For amateur installers, perhaps the best advantage of PEX is that it does not require soldered connections (like a copper pipe) or tricky threaded connections (like galvanized steel). PEX also requires fewer connections and fittings overall, which helps to lower costs and decreases the chances of leaks. Typically, PEX can be installed more quickly than any other plumbing pipe used for water supply.