Webflow is strong for many agency marketing-site projects, but application logic, complex commerce, infrastructure requirements, plugin dependencies, or client constraints can make another stack better.

An agency should not standardize every project on Webflow simply because the team is fast in it. A good agency standard has clear exceptions, and those exceptions should be based on the client's operating requirements rather than personal tool preference.
If the project is primarily a web application with authenticated product state, complex permissions, server-side workflows, or deep backend logic, a dedicated application stack may be more appropriate.
Large catalogs, inventory, fulfillment, subscriptions, advanced discounts, global tax, marketplace integrations, and other operational commerce needs can point toward a dedicated ecommerce platform.
A mature WordPress plugin, enterprise CMS integration, proprietary backend, or organization-wide technology standard may be more valuable than moving the marketing site into the agency's preferred builder.
Some clients require direct server control, specific hosting environments, deployment processes, security architecture, or source-code ownership that do not align with a managed platform workflow.
A marketing site that is likely to evolve into a complex logged-in product, marketplace, or transactional application should be evaluated against that future state rather than only the launch requirements.
If the client's internal team is already standardized on another CMS and has no desire to adopt Webflow, forcing a new system can create more operational cost than it removes.
Design-led marketing sites, portfolios, professional services, SaaS marketing sites, campaign properties, and structured CMS websites are often excellent fits when the team values visual control and managed publishing.
A mature agency standard includes a decision framework, not a rule that every project must use the same platform. Standardize the projects that fit; choose another stack when the client's requirements clearly win.