In real-time systems with millions of lines of code, no debugging capabilities outside of logs, and user misuse use cases, you'd be surprised what can lurk beneath.
That said, they won't catch a ton of memory and thread safety issues. You'll need tests with 100% coverage for that. Or you could just write it in rust and the compiler will catch it.
And full agree, all what cppcheck does imo should have long gone into the warning suite, and Werror and Wall should be the default..