[mjlawson]

I would argue that this too is part of software development. You ought to have a robust process that can accommodate hotfixes while minimally impacting ongoing work. That fix requires you to get buy-in from all of the right stakeholders, and the deployment requires you to follow the same processes as the development team.

I'm not sure if I see the value in making such distinctions though.

[mongol]

Yes it is part of software development in a larger sense. But there is value in it if you work as a manager. When you create your budgets you need to have an idea about how this work is split proportionally, because the work affects revenue in different ways. From a budget point of view, you can see it like: there may not be enough money to fund new feature development and the effect of that would be unfortunate. But if there also is not enough money to fund maintenance, it is worse.