In total I used anoraks for about 2 decades by now and probably won't anymore, for exactly the reason you mention: none of them were really convenient to get on and off, and if they were sort of convenient then it was because they were somewhat too big. In the end I just liked the single frontpocket (warm for your hands) and look.
And most of what seems like advantages are actually that: in comparison with a decent jacket with zipper it's not more windproof, nor more waterproof (zippers+flaps have been figured out for a long time), nor did I find them easier to pack. Even though the latter should be true in theory I cannot say it ever bothered me, and I have the impression that what makes a jacket hard to pack is wrong technique and mainly how thick the fabric is, zippers shouldn't play any roll (pun intended - the roll up just fine). Anoraks could be lighter though.
And most of what seems like advantages are actually that: in comparison with a decent jacket with zipper it's not more windproof, nor more waterproof (zippers+flaps have been figured out for a long time), nor did I find them easier to pack. Even though the latter should be true in theory I cannot say it ever bothered me, and I have the impression that what makes a jacket hard to pack is wrong technique and mainly how thick the fabric is, zippers shouldn't play any roll (pun intended - the roll up just fine). Anoraks could be lighter though.