Why should service boundaries in a refactored COBOL application align with business domains?

Think of it like working hands-on with IBM mainframe systems — the answer here is 'Business domain alignment ensures each service has a clear ownership team and a scope that evolves with business capabilities'. Aligning service boundaries with business domains ensures each team owns one cohesive capability, reducing cross-team dependencies and making each service easier to evolve, test, and deploy independen. On real mainframe exams, this concept comes up repeatedly so make sure you have it locked in.