Possibly in the sunny climate of beautiful italy a higher viscosity oil is recommended, but 5w30 vw507 spec oils are just more advanced and offer better protection to all engines than more simple oils.
In my old 1998 volvo I always used 0w40 synthetic, which is a higher spec than asked for by volvo at launch, but its still a better oil, amd that car did 180,000 miles before I sold it.
Synthetic oil has been sold for more than 25 years,but its only become common in the last 15 or so. Naturally I am speaking for the UK market, so our customs and beliefs might be different!