Two nodes in the automation canvas both work with your saved data elements — charts, tables, candlesticks — and their names alone don't make it obvious which one to use for what. This is a short, direct answer: use Apply Template for anything you're publishing, and know what the standalone Element node is (and isn't) for.
Apply Template: the one that actually publishes
If you've added a chart, table, or candlestick to a slide while designing a template, the Apply Template node picks it up automatically the moment you point it at that template — no separate wiring required. Its config panel exposes the element's inputs (a candlestick's prices and dates, say) as bindable fields right alongside your text {placeholders}, and running it produces a real post with both filled in. This is the fully working path — see binding charts and tables into posts for the mechanics.
Element: resolves data, doesn't render it yet
The standalone Element node looks similar on the surface — pick one of your saved elements, map upstream data to its inputs — but its current job stops one step earlier. It resolves your mapped fields into the shape the element expects and passes that resolved data along; turning that into an actual rendered, publishable image is explicitly a later-phase integration, per the node's own code comment. Today, running it doesn't produce a finished visual you can post on its own.
The practical rule
If the goal is a published post: always Apply Template, with the chart/table/candlestick placed on the template's slide at design time. The standalone Element node isn't the tool for that today, even though its name suggests it might be. Reach for it only if you're deliberately working with resolved data for some other purpose in your workflow — not for getting a visual onto a post.
Why this distinction matters
Automation canvases evolve, and it's normal for a product to ship a node ahead of its full capability — the Element node exists because standalone-element rendering is clearly on the roadmap, not because it's a dead end. The trap is discovering the gap by building a workflow around it and getting a post with a missing chart, rather than knowing upfront which path is finished. Bookmark this rule, and revisit it if you ever hear the Element node's rendering has landed — the config-panel version is exactly the same either way, so the only thing that changes is what happens when you run it.