Variant Half-Elf: is this meant to be Keen Senses AND another trait?

Question

The Sword Coast Adventurer's Guide says:

Some half-elves in Faerûn have a racial trait in place of the Skill Versatility trait. If your DM allows it, your half-elf character can forgo Skill Versatility and instead take the elf trait Keen Senses or a trait based on your elf parentage:

Emphasis mine. The traits based on parentage are things like swim speed for aquatic elves or magic for drow parents. But here's the thing. Skill Versatility is

You gain proficiency in two skills of your choice.

while Keen Senses is

You have proficiency in the Perception skill.

Why would one ever pick Keen Senses over Skill Versatility (with Perception and another skill)? Is this a design oversight, or a typo where it's meant to be "and", or is there something about these traits that I'm missing?

Answer 1

The Keen senses option is indeed inherently weaker

Your analysis regarding the Keen senses is correct - it gives you proficiency in a single particular skill when you could have proficiency in two skills of your choice. This issue is known yet uncorrected: In a 2015 tweet DnD 5e's lead rules developer Jeremy Crawford acknowledges it as follows:

The half-elf's Keen Senses option in the SCAG is, alas, superfluous. Take one of the juicy options below it.

This confirms that it indeed is an "or", not an "and".

The most recent errata for Player's Handbook and SCAG contain no mention on changing these rules, so until further revisions you can treat taking Keen senses instead of the Skill versatility as a valid, if nonsensical option of the game.