My observations on coping with lossy images and still being scannable were from personal experience testing rather than hard evidence, but I also read the MS research papers and how much they'd put into just that aspect, as well as giving a higher information density than b/w codes. Milage will of course vary.

Re:anylitics - not everyone runs a website to enable this an not all sites offer it. Eg, a group may wish to Market themselves on facebook and would like to know which media they advertise in gets the most hits - tags could do that and it gives an all in one interace for it.

Sure, you could do similar by directing a QR code via a similar service, but it's not integrated into a single off the shelf solution.

Hence my analogy with VHS/Betamax - one may be technically better (tags) but get the marketing wrong (not being open etc) and hence fail.