Both blocks call a URL and read back JSON, they just show it differently.
Api Fetch: one or a few values
Add rows under Result Fields (a label, a dot-path like current_weather.temperature, and an optional suffix like °C) and Api Fetch shows one "label: value" line per row instead of the raw response text. Leave Result Fields empty and you get the original behavior back, the raw response body as plain text, useful while you're still figuring out the shape of an API's response.
Api List: a whole scrollable list
When the response is an array (or contains one), Api List is the better fit: point Items Path at the array (leave it empty if the response body itself is the array), then Title Field/Subtitle Field/Link Field at fields within each item. Set a Link Field and tapping a row opens it in the browser.
Tip: Dot-paths support array indexes too, e.g. "results[0].name", figure out the exact path by fetching once with Result Fields/Items Path left empty first, so you can see the real response shape.