Data pack vs plugin for Minecraft servers
Both add features to Minecraft. They differ in what they can reach and where they run.
See which elements work as data packs
A data pack
Built into the game. It runs on vanilla servers, Realms and single-player worlds, needs no extra software and is safe to share as a folder. Its limit is that it only reaches what the game exposes to it.
A plugin
Software that runs on a server such as Paper. It reaches much more of the game and other plugins, so it can do things data packs cannot. It needs a server that allows plugins and some care when the game updates.
How to choose
If a data pack can do it, it is the lighter choice: nothing to install and nothing to keep up to date. If you need permissions, an economy, or events the game does not hand to data packs, use a plugin.
How Elementium handles it
You build the same flow either way. Each element is marked yes, partly or no for data packs, so you know before you export.
Questions
Can a data pack replace a plugin?
For some features, yes. For anything that needs a server-side library or an event data packs never see, no.
Which is safer?
A data pack has less reach, so less to go wrong. Either way, only install things you trust.