A few years of freelance/contract work taught me something annoying: the actual work was fine, but the business layer was chaos. Scope lived in email threads. Approvals were "did they ever reply to that?" Invoices were a separate tool I'd update from memory at month-end. I lost money twice to scope creep I couldn't prove.
So I built Stria — one system that runs a client engagement from scope to payment: clients, projects, deliverables, client feedback/approvals, invoicing, and payments via Stripe Connect. The client gets a feedback loop built in, so approvals are timestamped instead of buried in email.
The strongest part is connecting scope, approval, and payment in one workflow. Timestamped approvals could turn scope creep from a recurring dispute into something that is actually visible before it becomes a billing problem.