There are some issues that an application developer is very good at solving, usually if they relate to application logic. And then there are other issues that

There are some issues that an application developer is very good at solving, usually if they relate to application logic. And then there are other issues that classical operations people tend to be much better at finding, such as weird network/storage/compute/whatever disruptions or starvation, wobbly load balancers or firewall rules etc. Of course, you can try to teach developers those skills as well, but then you could also teach operators more about application logic. My point is that neither "developer on call" nor "operations on call" feel obviously right to me, and I haven't found a good solution yet. Maybe both need to be on call, and collaborate.