LDP gave us BGP-free cores. Don't underestimate how much that changed the game in large networks. BGP converged faster and core routers didn't need to do anywhere near as much. SR is a better way to do that now and LDP/IGP sync was a huge pain, but IMO BGP-free cores changed the SP game as much as route reflectors did.

LDP also enabled L2VPN and was an IGP-bound mechanism to enable MPLS VPN, which was always the killer app for MPLS.

LDP by itself? Meh. But it opened up a whole lot of other possibilities.