As it happens, I like the gegs clue. The 49a not so much. It splits the room as you say.
Why, well my bet is that most people needed lots of letters before they could get the picture and then get the pun.
Not so much bingo! wow that is clever (as with gegs) but "oh, now I got the clue I see the smart joke". The setter thinking what a clever, clever smarty pants I am to think of that a dreaming of crossword history. I just groaned.
My point is that you could be faced with no letters and get the scrambled idea just by thinking hard but I think very few could do the same with our mad greek. I didn't.
Opinions may vary but that's mine.