Haven't seen it mentioned yet. Another reason to learn assembly (why I am right now) is for debugging closed source apps to earn bug bounties.
You have a few different groups of apps to target, with different rewards and challenges.
Web apps, open source apps, closed source programs.
Looking for bug bounties, the first pays less and there's tons of people looking for the same bugs. The second group is usually not going to pay unless you're looking at the Linux kernel or a specific server. You can use many source code analysis tools on these. The closed source apps are where the real money is at. Browser escapes, media player RCE, OS exploits, you'll need assembly skills to debug these and see what's going on internally. This is where you find $100,000 bug bounties.