Is it still worth building an invoice generator SaaS in 2025?

A solo developer is nearing completion of an invoice generator SaaS aimed at freelancers and small businesses. Initially conceived as a personal, privacy-focused, and fast tool, the developer now questions its viability given the existing market. The current version emphasizes a minimal and fast user interface. It features simple subscription-based pricing without complex tiers. A core principle is privacy-first, with no tracking or data selling. The workflow is designed to be freelancer-focused, prioritizing speedy client and invoice creation over bloat. The developer's goal isn't to innovate but to offer a cleaner and lighter invoicing solution. They are seeking input on whether a new invoice generator would still find an audience in today's market. Advice is also requested on what features would make an invoice generator stand out in 2025 and how to validate a SaaS before launch.