Therefore, it is by no means state of the art and there are plenty of reasons that can argue against installing it. However, they are by no means violating the state of the art.
Sorry to contradict you. Of course, there are individual reasons against it. But if I see what is being built for work reasons (and that is apartments worth over €100 million every year), then the bathtub on the raw concrete floor is the absolute standard.
If you have no experience in the matter and generalize from yourself to others, it is not helpful for the OP.
Just last week, I looked at four apartments in Düsseldorf during acceptance (the most expensive was just under €3 million), where only one freestanding bathtub was present (but the bathroom was about 70 sqm). All the others were, albeit luxurious, normally installed.
If you have space and money to treat yourself to a freestanding bathtub, then I am happy for you. But then you belong to the few homeowners who can and want to afford that.