My players and I are unsure what ability modifier ranged and melee touch attacks from spells use to hit. Typically, ranged attacks use Dexterity, and melee attacks use Strength. However, spells also have the concept of Spell Rolls, which use the key mental ability for the class.
The Spell Attack section of the Core Rulebook states:
Your proficiency modifier for a spell’s attack roll is the same as your proficiency modifier with spell rolls...Melee touch attacks have the finesse trait.
From these two sentences I inferred that a Spell Attack Roll is different than a Spell Roll. Specifically, the finesse trait would have no meaning if a mental ability score were to be used. However, my players argue that ranged and melee touch attacks are some of the only uses of the spell roll, and it doesn't specifically state that spell attacks don't use the casting ability score.
Are there any rules we're missing or examples of spell attacks that indicate which of these is correct?