Charm protection is advantage, not immunity

Fey Ancestry improves saving throws against the charmed condition but does not make every charm effect automatically fail.

Magical sleep is prevented

Magic cannot put the 2014 Elf to sleep.

Unconscious is broader than sleep

An effect that causes unconsciousness without putting the target to sleep is not automatically negated by Fey Ancestry.

Trance replaces the Elf's need for ordinary sleep

The Elf meditates for four hours while remaining semiconscious and gains the rest benefit defined by the trait.

Trance does not automatically shorten every party activity

A shorter personal rest requirement does not make travel, another character's long rest, spell preparation, crafting or other downtime instantly finish four hours earlier.

Later Elf versions use updated wording

Astral Elf and Monsters of the Multiverse Elves have modernized Trance wording with flexible proficiency benefits. Do not import those benefits into the 2014 core Elf.