I'm using this cable with ubiquiti poe switches to power a couple of wifi access points. They work flawlessly despite the thinness. Probably the only thing you need to worry about that you don't kink / bend them to extreme degrees (they are not as flimsy / sensitive like fiber cable) but due to the thinness they obviously have no shielding or protective layer on the inside.
Now I have found a solution for me
With these Category 7: Lindy network cables (2m, Black, S/FTP, Cat. 7) my switch shows me 1 Gbit.
With these category 6 cables: Lindy network cable (2m, Black, S/FTP, Cat. 6) my switch only shows 100 Mb
I can only speculate what the reason is, attenuation etc.