Frank Erskine wrote:
given the list of cons mentioned, why r they used?

They're cheap :-)


they're crap.
Plumbers are old fashioned and dont like to change to easy fittings.

I am referring to flexible hose connections for whb's and flexible
waste pipes etc
they can be fitted in a few minutes whereas bending copper and cutting
and joining pipes makes a big job out of a little one.

I always use the ball valve now for sheer convenience and ease of
opening.
gate valves almost always are stuck and you never know if they are open
or closed.