Edit 1: I had swept this under the rug, but it is possible to take care of the phase ambiguity of $\psi(\mathbf{x})$ by dividing it with a non-zero scalar-valued quantity with the same kind of homogeneity. So $\psi$ is really a smooth function on $\mathcal{C}$ with values in the vector space
$$ \bigotimes_{\alpha \in \Phi} \mathbb{C}^2. $$
Edit 2: given an irreducible representation $V$ of $\mathfrak{g}$ corresponding to a dominant integral weight $\lambda$, we can choose a vector $0 \neq v \in V$ corresponding to the weight $\lambda$. If we then consider the principal $\mathfrak{su}(2)$ in $\mathfrak{g}$ with special element $H$ given by $2 \delta^\vee$, where $\delta^\vee$ is half the sum of the positive coroots (I forgot the corresponding formulas for the $E$ and $F$ elements), then under that representation, the $\mathfrak{su}(2)$ orbit of $v$ defines a representation of $\mathfrak{su}(2)$ which I think is irreducible (is this always the case, please?). Let us denote it by $W_\lambda$.
We could have started with an element say $\lambda'$ in the Weyl orbit $W.\lambda$ of $\lambda$. A construction of mine, generalizing the Atiyah problem on configurations, assigns, to each choice of $\lambda' \in W.\lambda$ a smooth function from $\mathcal{C}$ to $\mathbb{P}(W_\lambda)$, where $\mathbb{P}(.)$ denotes the projectivization operation.
Moreover, using the previously mentioned smooth functions defined on $\mathcal{C}$, one can construct a smooth complex-valued function defined on $\mathcal{C}$, which generalizes the Atiyah-Sutcliffe determinant, starting from a choice of $V$. Such a function is Weyl-invariant and is also invariant under an action of $SO(3)$ on $\mathcal{C}$. I feel like such a function is naturally associated to each choice of irreducible representation of $\mathfrak{g}$ (this vaguely reminds me of the geometric Langlands program, which I know very little about, but I am getting too speculative now, so I will stop).
What kind of applications may such concepts have? I don't know. I just feel these are natural objects to consider.