What kinds of attacks can the dhampir lineage's Vampire Bite trait empower?

Question

I am playing a dhampir Grave cleric for an upcoming campaign. The description for the dhampir lineage's Vampire Bite trait says, in part (VRGtR, p. 16):

When you attack with this bite and hit a creature that isn’t a Construct or an Undead, you can empower yourself in one of the following ways of your choice:

• [...]
• You gain a bonus to the next [...] attack roll you make; the bonus equals the piercing damage dealt by the bite.

What kinds of attacks can the dhampir's Vampire Bite empower?

I'm assuming this would only be for any attacks I make with my dagger or crossbow – is that correct? Is there any benefits with my spellcasting that would be good to use it with?

Answer 1

It empowers your next attack roll of any kind

You gain the bonus on the next ability or attack roll you make. Whether the attack roll comes from a weapon attack or a spell attack does not matter; it just needs to be an attack roll.

From the description of the Vampire Bite trait (VRGtR, p. 16; emphasis added):

You gain a bonus to the next ability check or attack roll you make; the bonus equals the piercing damage dealt by the bite.

As examples of spells that involve an attack roll, two such first level cleric spells are guiding bolt ("Make a ranged spell attack") and inflict wounds ("Make a melee spell attack").

Answer 2

Attack rolls encompass both spell attacks and weapon attacks.

An attack roll is defined (Basic Rules, Chapter 9) as:

When you make an attack, your attack roll determines whether the attack hits or misses. To make an attack roll, roll a d20 and add the appropriate modifiers.

There are in total 4 main categories of attacks, all of which use attack rolls:

• Melee weapon attacks (e.g. a longsword)
• Ranged weapon attacks (e.g. a crossbow)
• Melee spell attacks (e.g. inflict wounds)
• Ranged spell attacks (e.g. guiding bolt)

Vampire Bite only mentions an "attack roll", and thus its empowerment can apply to all of the above attacks. If it was meant to only work on weapon attacks, it would have specified that.