annodomini, IMO M&S have always been notorious for spoiling something that might have been nice enough, with fussy details or added ‘bits’.
I do still find the odd thing, but mostly I think their buyers/designers have had a taste bypass, or are colour blind, or both.
Or else they just think, ‘Well, I wouldn’t be seen dead in it, but it’ll do for M&S.’.
I still have a nice summery cardigan I bought at least 5 years ago, that came with the most ghastly buttons - like those leather ones on old men’s cardigans, only plastic! Whatever possessed anyone to choose them, I can’t imagine.
Having bought it, I went straight to John Lewis for some infinitely nicer ones. It was well worth the effort of stitching them all on, since I’ve worn that cardigan endlessly, and it washes like a dream.