Dynamic content means the post changes because the data changed, but "the post" isn't one uniform thing — a carousel and a reel are genuinely different editors with different layouts, and dynamic binding behaves a little differently in each.
Two separate editors, not one hierarchy
The carousel editor builds multi-slide image posts — placeholders can live on any slide, and a data-bound carousel might use one slide per data point (see 15 dynamic content ideas for examples like a multi-bullet news digest, one point per slide). The reel editor is structurally different: a video with top, video-band, and bottom cells, including a "banner" cell type that renders a constrained avatar-name-handle-verified-badge overlay, intentionally limited to colors, caption size, and avatar shape rather than open layout.
What stays the same regardless of editor
The actual mechanism — an HTTP Request or Custom Agent node feeding an Apply Template node — works identically whether the destination is a carousel or a reel template. The data source doesn't know or care which editor built the template it's feeding; the binding step is the same concept in both places.
Where the reel editor's constraint is a deliberate feature
The banner cell's limited styling — you can adjust colors and caption size, not rebuild the layout from scratch — exists specifically so a bad or unusually long data value can't break the design. A carousel's more open layout gives more creative freedom but also more surface area for a malformed data value (an unexpectedly long name, a missing field) to visually break something. If your data source is less predictable, the reel editor's constraint is protective, not limiting.
Picking the right editor for a given dynamic format
A format with several distinct points worth showing separately — a multi-bullet digest, a step-by-step breakdown — tends to fit the carousel's slide structure naturally. A single, punchy data point with a recurring presenter-style layout (a recurring price update, a recurring commentary format) fits the reel editor's more constrained, repeatable structure well. Neither is universally better; they suit different data shapes.
The takeaway
Don't assume "dynamic content" implies one specific template type — the concept is the mechanism (real data, bound via placeholders, published automatically), and it applies to both editors. Choose the editor based on what your data actually looks like and how many distinct points it needs to convey, not based on which one you happened to build first.