What are other good attack examples that use the hash collision?
Collisions are a generic tool in many attacks beyond hashes. Examples:

Attack of double encryption $C=E_{(K_1,K_2)}(P)=E_{K_2}(E_{K_1}(P))$ given a few (say 2) plaintext/ciphertext pairs $(P_i,C_i)$, which basically finds a collision between $F(K_1)=(E_{K_1}(P_1),E_{K_1}(P_2))$ and $G(K_2)=(D_{K_2}(C_1),D_{K_2}(C_2))$.
Discrete logarithm, in Baby-Step/Giant-Step and it-s memory-lean variant Pollard's rho. Basically these solve $x[G]=A$ in some group (noted additively) with generator $G$ by finding a collision between $y[G]$ and $z[G]+A$ with $y$ and $z$ from disjoint sets, then get $x=y-z$ modulo the group order.
Integer factorization, using a different Pollard's rho.

The reduction of the effort from $O(n)$ to $O(\sqrt n)$ characteristic of collision search, combined with the possibility of parallel collision search on independent machines with little memory*, is what makes these methods attractive. For 1, and 2 in the case of a generic group, this is the best known method.

* See Paul C. van Oorschot and Michael J. Wiener's Parallel Collision Search with Cryptanalytic Applications, in Journal of Cryptology, 1999.