The best practice is to actually enqueue from the bundled version since it has a handle, this avoids conflicts.
If 2 scripts are enqueued using the same handle, jquery-ui-core for example (default WP one) then only 1 script is loaded.
If 2 scripts are enqueued using different names then they will both be loaded.
This is especually true for scripts and CSS like jQuery-UI which include thier own hardcoded handles like #tabs which can cause problems with themes and other plugins.
In my opinion breaking a site is worse than having to load a few extra KB’s.