[RPG] Can elves trance in armor without any downsides

An elf receives the benefits of a long rest in 4 hours while using the "Trance" trait.

According to the 2017 update to the Sage Advice Compendium:

Q: Does the Trance trait allow an elf to finish a long rest in 4 hours?

A: If an elf meditates during a long rest (as described in the Trance trait), the elf finishes the rest after only 4 hours. A meditating elf otherwise follows all the rules for a long rest; only the duration is changed. This answer has been altered as a result of a tweak to the rules for a long rest, which appears in newer printings of the Player’s Handbook.

This ruling reverses guidance in the earlier version of the SAC, due to errata changing the rules for long rests.

Interactions between the "Trance" trait and long rests

A long rest is defined as:

... a period of extended downtime, at least 8 hours long, during which a character sleeps for at least 6 hours and performs no more than 2 hours of light activity, such as reading, talking, eating, or standing watch.

The elf's Trance trait is defined as:

Elves don’t need to sleep. Instead, they meditate deeply, remaining semiconscious, for 4 hours a day. (The Common word for such meditation is “trance.”) While meditating, you can dream after a fashion; such dreams are actually mental exercises that have become reflexive through years of practice. After resting in this way, you gain the same benefit that a human does from 8 hours of sleep.

Since the "Trance" trait replaces the need for sleep (which most races need in order to complete a long rest), the elf is able to satisfy the requirements of the long rest while in a semiconscious trance for four hours.

A few folks have mentioned to me that Mike Mearls has stated elsewhere that it's an oversight in the text, and the intent is that a level 1 character should recover 1 hit die. Seems likely errata-fodder.

@MrMattFree : Hit dice question! Basic rules say you get half your HD back at a long rest but doesn't say round up. What does a 1st lvl do?

@mikemearls : should be minimum 1.

The rules for long rests were later updated to say that the minimum is 1 hit die.

The character also regains spent Hit Dice, up to a number of dice equal to half of the character’s total number of them (minimum of one die). (PBRv0.2 p.67, PHB5e p.186)