On the one hand, it was mind-numbingly delicious because of the White Witch's magic making it incredibly addictive, rather than simply the virtue of being Turkish delight.

But why the choice of Turkish delight? A combination of status-signalling and unavailability [1] (post-WW2 sugar-rationing was still in effect when the book was written).

[1] http://www.tor.com/2016/08/08/why-was-turkish-delight-the-ul...