Actually debug Tools don't help with crash, they often use classic GL introspection functions so that they will provide the same reports as arb debug output. Tools from IHV only give access to the performance counters of their hardware while frame capture is vendor agnostic as far as I know.
On the other hand they're really useful to debug visual glitches as they record framebuffer content after every draw call which allows to detect which call is not correctly working and see all the state parameters (blend, depth text, constants...).