How does the "Day Drinker" thin-blood merit work?

Question

Day Drinker is an interesting thin-blood merit; it reads:

Sunlight halves your Health tracker (rounded up), but otherwise simply removes your vampiric abilities, including all Disciplines and Health benefits, and does no other damage. You still suffer from Hunger, however, and sooner or later you’ll need to sleep. If your health drops below your currently sustained damage levels as a result of this, you suffer the effects of Impairment or torpor (depending on type of damage) until you are clear of sunlight.

English is not my first language, so I'm not sure which interpretation is correct:

• You can choose, when you take it, whether it halves your health tracker or makes it so you can't use your vampiric abilities in daylight
• Both happen: It halves your Health tracker, and makes it so you can't use your vampiric abilities in daylight

Do you choose one of the two results, or do both occur?

Answer 1

Both.

Ordinary vampires, when exposed to sunlight, take a number of levels of Aggravated damage each turn equal to their Bane Severity. (p.221)

Thin-blooded vampires, when exposed to sunlight, take one level of Superficial damage each turn. (p.113)

Thin-blooded vampires that have the Day-Drinker merit do not take any damage from sunlight. However, while exposed to sunlight, their health tracker has half the usual number of boxes and they may not use supernatural powers or disciplines. (p.183)