I believe most commercial logic probes are a little bit more complex, with features like pulse stretching, ability to show pulse trains, detecting tri-stated outputs and a memory.
I don't think they're terribly useful in modern electronics, especially if you have a scope, but I use one (HP 545A) occasionally for signal tracing or spotting bad connections. The ability to distinguish between high, low and tri-state is something a scope can't easily do. They're only useful for simple signals, however, not much point using it to troubleshoot an I2C bus.