Simple-type conjecture for Seiberg–Witten invariants

Let $X$ be a manifold of simple type. For a choice of $Spin_c$-structure $L$, let $M_L$ be the Seiberg–Witten moduli space and let $d=\dim(M_L)$. Simple-type conjecture. The only non-trivial Seiberg–Witten invariants correspond to choices of $L$ such that

$$d=\dim(M_L)=0.$$

This conjecture asserts that positive-dimensional Seiberg–Witten moduli spaces do not contribute non-trivial invariants for manifolds of simple type. The source calls it a related conjecture but provides no resolution evidence.