I’m not familiar with the Kutzmann carriages, but all of the carriages we have ordered have “quick change” hubs. This way we can train with the pneumatic wheels at home and then change it out for the hard wheels for competing (for CDE’s). At a CDE, you cannot drive with pneumatic wheels. They must be hard rubber.
We love using the pneumatic wheels as they dig less into our sand ring when we are starting to fit up our ponies after the winter off. They also give a nicer ride for the driver and passengers. I do reccomend them for every day use 
That brand is more of a CDE carriage, so not a show pleasure carriage - so you will not be able to enter in a “regular” single horse division, but a lot of pleasure shows now have a division just for marathon carriages. They tend to get quite a few entries in this division as its an expensive sport and not everyone can afford 2 carriages.
If you can, I would purchase both sets of wheels and make sure you ask for a “easy change” type of hub. It saves a lot of time when you have to switch the wheels out (ask me how I know!).