Feynman knew physics but he didn't know ornithology. When you name a bird, you've actually identified a whole lot of important things about it. It doesn't matter whether we call a Passer domesticus a House Sparrow or an English Sparrow, but it is really useful to be able to know that the male and females are the same species, even though they look and sound quite different; and that these are not all the same thing as a Song Sparrow or a Savannah Sparrow. It is useful to know that Fox Sparrows are all Fox Sparrows, even though they may look extremely different depending on where you find them.

Assigning consistent names to the right groups of things is colossally important to biology and physics. Not being able to name birds for an ornithologist would be like a physicist not being able to say whether an electron and a positron are the same thing or not. Again it doesn't matter which kind of particle we call electron and which we call positron (arguably Ben Franklin screwed up the names there by guessing wrong about the direction of current flow) but it matters a lot that we always call electrons electrons and positrons positrons. Similarly it's important for a chemist to know that Helium 3 and Helium 4 are both Helium and not two different things (at least as far as chemistry and not nuclear physics is concerned).

Names are useful placeholders for important classifications and distinctions.