A vendor comparison should begin with the complete workflow, not a feature checklist. A product may generate an excellent answer and still fail because it cannot read the source of truth, preserve permissions, show why an answer was produced, route uncertainty to the right person, or write the accepted result back to the system where work continues.
Buying is usually sensible when the task is common, the product is mature, the data terms are acceptable, and configuration can close the remaining gap. Custom development becomes more defensible when the workflow creates meaningful differentiation, several systems must behave as one, customer experience matters, or the organisation needs tighter control over evaluation, data, and change.
A hybrid path is common. The business can use a commercial model, document service, or automation platform underneath an owned workflow and evaluation layer. The decision record should state what the organisation owns, what it rents, what happens if a provider changes price or capability, and how difficult it would be to switch.