Every business has at least one operational problem that no SaaS solves cleanly. A weird industry workflow. A regulatory requirement. A data structure that doesn't fit anyone's template. A competitive advantage that depends on doing something nobody else does.
The usual options are bad. Hire a junior developer — they ship slow, leave fast, leave you holding a codebase nobody else can touch. Engage a big agency — they're expensive, slow, and treat you like a small fish. DIY with no-code — works until it doesn't, then you're rebuilding from scratch.
Custom Development is for the problems that deserve a senior engineering partner — but don't need a five-person team or a year-long commitment.