As far as I know, most airlines do prefer ILS approaches as a company policy. At EHAM we fly quite some RNP approaches, for instance, during nighttime we fly night transitions following by an RNP approach as the standard. As mentioned, RNP approaches are still considered as non-precision and ''must'' be intercepted via the IF by most airlines (e.g. KLM as far as I know). So, from ATC perspective, short approaches, direct headings towards the FAF or not an option with RNP operations. Besides, from safety perspective RNP appproaches are even not allowed in loads of situations (e.g. converging approaches, reduced visiblity etc etc).
Interesting topic
