If I could extend this concept a bit, I think two of the really big factors in where people manage their tasks are where the work is and where the work starts.
For example, take email. For many workers, their work starts in email: they get tasks delegated to them from their boss, they get partially done work from colleagues for them to do then next step on, they get finished work from subordinates for review, etc. This explains why so many people use their inbox as a task list (despite how ill suited email is for that). Throw in the fact that for many managers email is also where the work is and the compulsion to use it for task management becomes almost irresistible.
On the other hand, take someone like Federico Viticci. His job (especially between WWDC and the iOS release date) is to do research, take notes, and write. Since he likes to do his notetaking and writing in the same app, there’s a big payoff to integrating his task management into that app. So odd as it may seem to many, it makes perfect sense that he’s commissioned custom Obsidian plugins to integrate ToDoist into his writing environment. @ryanjamurphy, based on your other post I suspect your situation is somewhat similar.
Similarly, for many people, meetings are where the work starts, which explains why so many meeting-oriented notetaking apps (Agenda, Noteplan, etc.) have built-in task management.
A somewhat less extreme version of this is to use a separate task manager, but to streamline capture from where the work starts. This can be particularly appealing when where the work starts and where the work gets done are not the same place (someone gets new tasks via email but does their work in a code editor, for instance). The near-ubiquity of email as the source of work tasks is why so many task managers have built-in methods of capturing tasks from mail messages. It’s also why I’m seriously considering writing some sort of automation to capture tasks from my meeting notes in Noteplan and automatically add them to Things.