Separate the need for a custom block from the need for custom code
A site may need a content component that behaves like a custom block without requiring a bespoke JavaScript project for every component. Visual or low-code block builders can define fields, templates and reusable output while letting WordPress handle the editor integration.
That can be a strong fit for structured marketing or editorial components where the data model is straightforward and the front-end output is mostly markup and styling.
Low-code works best with predictable content models
Blocks built around text, images, links, selections, toggles and repeatable items are often good candidates. The editor needs to expose those fields clearly and the renderer needs to map them into accessible HTML. The value comes from reducing boilerplate, not from pretending that every possible interaction can be configured visually.
Custom code still wins for complex editor behaviour
If a block needs a highly interactive editing canvas, complex client-side state, unusual data fetching or deep integration with another JavaScript application, direct development can provide the control you need. A low-code tool should not become a maze of workarounds that is harder to maintain than a small purpose-built block.
Keep generated output portable
Evaluate what happens if the builder plugin is disabled or the block definition moves to another site. Understand which data is stored in post content, which settings live in the database and which templates are required at render time. Portability matters especially for agencies handing sites to clients.
Choose based on ownership and maintenance
The technical question is only half the decision. Ask who will maintain the block in twelve months. If the team is comfortable with a JavaScript build pipeline and needs deep control, code may be appropriate. If designers or site builders need to create and adjust structured blocks without rebuilding a plugin, a visual workflow can be more sustainable.