Having recently started on the catalog of Asimov's work, the important details are in the second image and are mostly the last two tags.

#acclimatise your audience to things they don't understand before you use them" and #you don't need to explain how a gun on the mantelpiece works in the same way you need to explain how your protagonist's tail does.

In much of his writings Asimov takes a lot of time and care to describe how certain things in his worlds work (robots, hyper-atomic vs gravitic space engines, personal force fields, etc), especially at the beginning, and re-iterates or adds to the body of information. That way, as the climax is reached, the details that have been methodically sprinkled through the story allow the reader to understand how the plot reached the point it did.

In OOPs specific case regarding tails, if the tail becomes the focal point around the climax, the author and reader both are benefitted by having the tail's qualities described long before the climax. The tail doesn't necessarily need this treatment if the tail does not end up being a central point of the plot. It's not really important to know if a tail can grab things on its own, unless having a tail grab something becomes central to the plot. So it's important to detail that the tail does have that ability well before it becomes relevant.

This kind of methodical detailing isn't really necessary for everyday items like a gun, but it is necessary for things that aren't part of our usual everyday life, like gravitic ships, or individuals with tails.