Most industries, especially tech, have translated the IT developed Agile methodology into standard business practice of how to deliver... well, just about everything. But does it work for the creative industries?
This way of project management has taken off because some software developers in Utah created it and big tech corps adopted it with success. Its benefit is you can deliver something in incremental stages, instead of planning, building and pushing live all in one go. It lets you test as you go, so you can fix any bugs and optimise anything you create and hypothesise.
It also manages workflow with kanban and sprint planning. And forces collaboration between copywriters, UX, designers, developers and product owners through scrums and daily stand-ups. This is also a good thing.
This only works when developing new sales journeys or functionality and during transformation. For BAU across P&Ls or for conversion rate optimisation (CRO), ringfencing resource is a waste of productivity. It also creates a single-point of failure.
The other issue is it creates silos within a silo. Having an X amount scrum teams with a digital department causes a lot of conflict and separates copywriters from their horizontal community. By keeping the same people on the same project, you're limiting ideas and not seeing the big picture.
I believe the studio model for in-house teams works. Pairing creatives with developers and UXers to spread their skills across other workstreams. You should always have an A-team for the those high-profile, top priority projects, but having a central team that get plugged into scrum teams on a project by project, sprint by sprint basis, depending on what skills are needed.
Of course, adapting another copywriter's work based on analytics and testing will bring a fresh pair of eyes and different brain, perhaps bringing a different dimension to what's there.