classical mechanics - Meaning of centrifugal term in the mechanical energy of a orbiting planet

For a planet under the effect of gravitational force the mechanical energy can be written as

$$E=\frac{1}{2}\mu {\dot{r}}^2+\frac{L^2}{2\mu r^2}-\gamma \frac{m M}{r^2} \tag{1}$$

Where $\mu$ is the reduced mass of the system planet-star.

Consider now the term $$U_{centrifugal}=\frac{L^2}{2\mu r^2}$$

This is a kinetic term in the mechanical energy expression (actually the one regarding $v_{\theta}$), but, since $L$ is constant, it has been rewritten as a function of the $r$ coordinate only. I read that this "makes" it a sort of potential term. That's clear, since it does not involve the velocity, but what is its real meaning?

The name "centrifugal" is because it sort of makes a "centrifugal barrier" which is the reason why the planets with non zero angular momentum stay in orbit instead of "fall" on the star.

I can see this from this graph if I think about the fact that kinetic energy cannot be negative.

But I still do not get the physical meaning of $U_{centrifugal}$. To what extent is $U_{centrifugal}$ to be considered a potential term and how does it prevent the orbiting planet to meet the star, mathematically, from $(1)$?