If you need deadlock detection, probably your high level design is problematic. But I agree this is extremely often the case, so that's extremely often an interesting and valuable tool.
After chasing a bug for hours just to discover that it is a deadlock, its always easier to realize, in hindsight, that deadlock detection would have been useful.
Independently of how perfect your architecture is, the moment you add a Mutex to your app, you are opening the door for that to happen.
More like the moment you add a second Mutex in your app, ad-hoc handling and no policy to prevent deadlocks.
The solutions are well known and I'm simply sad to see them far too little used.
But in the case you insist in doing that (not using architectural solutions, some of which can be checked statically), yes of course runtime deadlock detection is a very valuable tool. I agree that it is even useful if you rely on policy but can't automatically check that they are respected.
I mostly agree with this except I think the bigger thing is that you should rarely be using locks in the first place. Instead use existing parallel data structures and atomics.
