@ALostInquirer As others have pointed out it is largely a matter of price and durability. My background is in industrial equipment so keep that in mind. It is worth noting what differentiates pipe from hosing at least in my industry, pipe is a tube made of a single solid material of a certain thickness, tubing is a single material tube of a thinner wall thickness, and hose typically consists of multiple layers or materials to maintain flexibility while still being durable. Some industries like medical may call a flexible tube of a single material a hose, but this is usually colloquial and not the official terminology found in standards and regulation.

Because hoses are made of multiple materials and typically laminated or woven and adhered together they are much more complex to manufacture, and so more expensive, often at minimum 5x as expensive. When you look at hoses meant to last for decades this can go up a lot, 10-20x, this is because flexible materials in general degrade over time and become brittle and/or porous, prone to springing a leak. The methods used to prevent this require expensive chemicals, or patented processes which keep prices high.

PEX is growing in popularity because it is flexible and durable but relatively inexpensive, only 1.5-3x as expensive in cost of materials as CPVC typically. PEX is a type of pipe/tubing made of Cross-linked Polyethylene, which is a singly polymer, Polyethylene, that has been either treated with a chemical such as a peroxide or silane, or irradiated with an electron beam, to induce cross-linking of the long-chain polymers. This Cross-linking makes the material much more durable and elastic, while requiring only a single treatment and no lamination or weaving. As such PEX can be manufactured more cost effectively than hose, making it a good middle ground between rigid pipe like cPVC or copper for potable water applications.