IMO you don't need a particularly powerful pump on a spotter. In the past, I have rinsed spots very effectively with a spray bottle, bone spatula and wet pick up vac.
You need a spotter to be very small and compact. Again this just an opinion, but the Karcher Puzzi is too big a machine for a spotter, both to carry and space wise in the van.
If I required a small compact spotter, I would be tempted to carefully look at the Vax Commercial VCW-02 Compact carpet washer. Small footprint, lightweight and, OK, the water delivery is very low, but there are ways as mentioned above. If, however, you required a little more versatility from a spotter such as the occasional dining chairs or even a bathroom, the Karcher would prove to be more attractive.
Like many here though, I do have the advantage of experience in the techniques required for spot and stain removal.
Safe and happy cleaning
The Ken