Different sources

Elf baseline: Basic Rules (2014). Astral Elf: Spelljammer: Adventures in Space / Astral Adventurer's Guide (2022).

Different ability-score design

The 2014 Elf has fixed +2 Dexterity plus subrace increases. Astral Elf uses the later flexible increase model provided by its source.

Different Trance design

The 2014 parent Elf uses the original four-hour Trance. Astral Trance retains the four-hour rest idea but also grants flexible proficiency choices after the trance.

Astral-specific active traits

Astral Fire provides a cantrip choice and Starlight Step provides limited-use bonus-action teleportation.

Shared elven features do not make the records interchangeable

Darkvision, Fey Ancestry and Keen Senses appear in both, but the complete species packages are distinct.

Why the rule packages stay separate

High Elf and Wood Elf are 2014 subraces that build on the 2014 Elf package. Astral Elf is a later standalone species design. Sharing elven ancestry does not make those rule packages interchangeable.