Not for a novelty value, they really have their uses.
The 6 wheel C15s were built for the narrow side streets in France, to deliver wine, flowers etc to back entrances of shops. There were many variants (although only a few were built), there were fridge vans, pickups, I have even seen a bin lorry version.
Our C15 has been excellent, it seats 5 people (has a rear footwell unlike the normal vans) it has a huge boot and its very refined too. I have driven Transits and even the new T5 VW but in van for they are so noisey, really surprising. Also a Transit or T4/T5 with seats is not a common sight and are options.
As for resale, we have had many an offer for our C15 and it would not be a problem to sell. Its also worth a lot more than a 15 year old Transit!
Everyone has a Transit or similar, why not have something different, somehting which stand out, a talking point, something no one else has and which appeals to a few people.
Our C15 was used for our Citroen specialist business for a lot of years, it then took over other duties when my dad changed jobs, it was ideal and better than a van because its cargo area and seats are split up. When it was retired we replaced it with a T4 VW Caravelle, which did the job.
As for the drive, the grip is excellent, stability is fantastic too. You might think it would want to push on, having 4 wheels at the back, but it doesn't. When pushing on its grip is excellent, it drives very well and its a joy to drive. Tyre wear is not bad at all, about 20K miles from the front tyres and 25K from the 4 rears.
Parts, well the rear side door is totally unique, and the side panels were fabricated. So if it was involved in an accident it would be extremely hard to repair and I doubt you could ever find another door. It also has other things such as the rear seats, foot well etc which are for this van. Therefore you could never make another genuine one either.
I like things that are different, its what makes life interesting! Anyone can buy a Transit.
The fact I often get people driving along side and taking videos/photos with their camera/phone of the C15 makes it rather special. For similar reasons is why we love our 6H and why its one of the most desirable of all Tractions. Its differet and often that is what is appealing about cars.
A CX Tissier is really something, if its an ambulance if offers an excellent ride quality, if its a car transporter stability and the ability to lower its suspension is ideal and for a loadrunner the self levelling its a real bonus.
Something which stands out is also ideal for business advertising, as you see the vehicle and then read the sign writing.
Above all, its the rarity factor and its something different, I like that.
And that is partly why I like French cars, as a lot of them offer something different than the opposition, even if it is something simple or something other people dont know about or apprciate.