Enqueuing scripts and styles in custom plugins

Straight outta the Codex:

wp_enqueue_scripts is the proper hook to use when enqueuing items that are meant to appear on the front end. Despite the name, it is used for enqueuing both scripts and styles.

So the simple answer to your question is yes, wp_enqueue_scripts is always the correct action for enqueuing scripts AND styles. This is so other themes/plugins can modify previously-enqueued files or other plugins (e.g. a minifier) can assume that all scripts/styles are loaded with that hook.