I would have thought that way better media storage and flexibility, and GPS where the strongest reasons to bother building a CarPC! Thats why I built mine
Factor the costs (3 years ago) for the following:
GPS Unit - £150-£500
Speed Cam detector - £50-£400
MP3 Multichanger - £100-£300
Phone Hands free - £50-£300
Wireless Internet - ?
OBD Monitoring - £300+ for my car
Add all that up and it costs a fair bit more than a CarPC (if you are prepared to build & setup your own).
That, and the pimpness of having something next to no-one else has

THAT I MADE MYSELF
Centrafuse just makes all this more accessible to non-techy people who may not be that great at configuring and tweaking programs like RR.
It also makes life easier for re-sellers and CarPC system builders as setup and config is way easier than other frontends out there and it has proven to be quite stable and reliable.
Destinator isn't perfect, but its all we have in EU at the moment! All that could change though when PC Navigator 7 comes out from Directions Ltd. Or if TomTom ever pull their thumbs out of their asses and do a PC version!
All that is IMHO obviously
