I learned something this week....

If i'm connecting a screw on tap tail to, for example, an isolator valve
i'll use a both end compression one and do away with the nut and olive
on one end.

But you're supposed to get a specific one with a flatter end.
This was news to me (not enormously surprising) and news to the guys at
the local hardware store (perhaps moreso).

Anyway they didn't have any so i'm using normal ones as usual, is this
an issue?