It's the rigmarole of getting it all type approved for the UK market. I think you'll find there was a KE-Jet 16V motor fitted in the areas of the world that went unleaded and catalyst before the UK. It was lower output and had KE-Jet (which is enough reason never to love any engine).
Bear in mind there are multiple vesions of Digifant, so Digi 1 on the 8V and on the G60 (these are all IIRC, which it's possible I don't), Digi 2 on the catalysed 8V and then Digi 3 (and 3.2 as well, I think) in the Golf3 16V.
I assume they went digi cos it is more reliable and I dare say cheaper to fit in production!
You can say it, but the key benefit is that it's also far more reliable and delivers better power than the plate and bowl BS in a K-jet motor.