Worth it would be relative to the situation.
If 35mm is your bread & butter, and you want the best 35mm you can get, it may be worth it if you absolutely must have Canon. But really, it's competing with a few lenses, namely the Sigma 35 ART which significantly less. If you already have a 35mm F1.4, then to me, it probably isn't worth it. Granted, the 35 F1.4L is an aged lens, the 35 F2 IS optically is better, etc. But it's F2 not F1.4. So the Sigma 35 ART made a ton of sense for people wanting a fast 35 F1.4 with AF. Then Canon finally drops the 35 L II, with an enormous price tag. Not worth it based on cost alone to me. Sigma ART being the better deal, for quite literally the same IQ. Again, if it's your bread & butter and you need Canon, then the 35L II makes sense. But if it's just for shooting kids around the house or something, I'd say no.
Since you're even considering the Zeiss, then I would say that answers a ton of questions right away about the need for AF, Canon, etc.