We tried the generic project-management tools first, like every agency does. They're fine for tasks and terrible for the actual shape of agency work: a client isn't a project, it's a standing relationship with a brief, a calendar, a Drive folder, a set of connected ad accounts and a monthly report — all linked, all live.
So Nexus exists because the alternative was six disconnected tools and a spreadsheet holding them together, which is exactly the kind of operation that makes a client feel like a ticket number instead of a relationship.
The same system, seen through a narrower lens, is what a client sees in Bloom. One data model, two audiences — that's the whole idea.