For me it’s down to absorbtion.
From the side of the joint causing framing to red wine stains on the surface.
As for surface wear the edges chip as you get them out of the box so in 3 months you’ll be back doing repairs, hence it’s not worth the effort/risk with alternate tiles available.
Not only would I not sell ceramics for floors, but I refuse to fix them. Customers don’t know as they just like the pattern, it’s up to the professional installer to make the decision.
I'm 50/50 with that opinion and to be fair, red wine can stain anything it comes into contact with if left to sit there for long enough. Even micro-textured glazed porcelain and sealed polished porcelain. Ceramics are not exclusive. Yes, the installer can make a judgement call, but would have thought it would be dependant on the end usage rather than a flat-out "no I ain't doing it". That's like saying that any ceramic floor tile ever made by any manufacturer, regardless of class is not fit for purpose, which is incorrect.
But each to their own opinion and if you have seen horrific problems, understandable you'd avoid them, but not all ceramics are the same. There are some very good ones about, which if fitted correctly would out-live all of us. (useless bit of information, but although a few have taken a violent jolting, some of the ceramic tiles used in the Turkish Baths on the Titanic are still intact in the wreckage, despite sinking 107 years ago... guess they don't make 'em or fix 'em like they used to
google it. Really interesting pictures)
Also agree that no-one checks the boxes for class, but 99% of the time, the information is there, and if it's not, the supplier will know or be able to find out. The likes of CTD or dare I say, Al Murad will correctly advise the use for which a tile is suitable, and if they say floor, take their word for it, they're not in the business of lying..... Well, except maybe in the OP's case of course.