Indeed - but as I said not actually PAL. That refers to phased
alternate line. And designed to overcome problems with
transmission that NTSC suffers from.

While introducing problems of its own, such as severe desaturation under
conditions of excessive group-delay error.

Wasn't being jingoistic, BTW. There is always a downside being first like
with NTSC. But I'm not sure what you mean by group delay?

IIRC was taught that NTSC gives the best off camera pictures, PAL for
processing and recorded to tape and SECAM for transmission?

NTSC and PAL are pretty much Tweedle-Dum and Tweedle-Dee. There's no
significant difference between them. PAL is essentially NTSC with phase
alternation. (Which was supposed to be part of NTSC, but the designers
couldn't see any way to build an inexpensivd TV receiver to take full
advantage of it, so it was dropped.)

At the time Europe adopted PAL, the transmission systems had a lot of
non-linear group delay (the US systems didn't), which alters the hue. The
phase alternation causes the hue shifts to be "opposite" (complementary) on
alternate lines, so there is a visual averaging of the hue. This is good, up
to a point, but as the averaging pushes the color towards white, the effect
is visible desaturation.