It's also newer so longevity probably makes better financial sense.
They've surely tested it back-to-back with the C3 and found it's faster.
The Lancia Ypsilon has not had any real run until now, so I guess people are just comparing(in their brains)to the Citroën C3 Rally2 ;)
By the way, no less than 30 Lancia Ypsilon Rally2 HF Integrale were sold(ordered) on the day of 19th november(the day after the presentation to the press in Satory) :)

O. Solberg Saudi PET https://www.youtube.com/watch?v=CDYkvGmYenQ
WRC Testing