Naively, one could topologise the set of smooth (ie $\mathcal{C}^\infty$) maps between two smooth manifolds $M \to N$ with the subspace topology $\mathcal{C}^\infty(M,N) \subseteq \mathcal{C}^0(M,N)$, where the usual compact-open topology is considered in $\mathcal{C}^0(M,N)$.
Now, why are the weak/strong topologies in $\mathcal{C}^\infty(M,N)$ considered instead? How different are they from the subspace topology as explained before? What are their advantages with respect to the subspace topology?