Hi Yveaux and Nca78, thanks a lot for taking the time to answer.
My german is rusty but I understand they're just hiding the sensor in a plastic pipe. That's a really shady way of "protecting" the sensor. Bugs would have the time of their life in these pipes. Also, it doesn't look professional at all.
@Nca78 The lower accuracy is remarkable as they are a lot more expensive. The original model is priced at €14 on TME, while the compact is €58 on Mouser
I don't understand why Honeywell doesn't provide a simple policarbonate case for these models...
Another famous sensor of this kind is the SPS30 by Sensirion. That one is even more compact, but again there's no standard enclosures on te market...