Begging your pardon, that's the way Gerald O'Donvan (AKA GOD) built all (as far as I know) the Raleigh SBDU bikes. It's not ugly, in fact it's rather attractive in a minimalist sort of way. I do realize, in this particular case, that there would be an unused cable stop on the down tube. While a derailleur with an integral stop is to be preferred, if one wasn't to be found this [routing under the BB] would be a perfectly suitable solution.