Cantrips scale with level in 5e, so casting a leveled spell + a cantrip can be quite powerful (though obviously not as powerful as to full spells). For instance, at level 6 a dragon sorcerer adds charisma bonus to damage of type that matches their origin. So a red dragon sorcerer casting firebolt will do 1d10+cha damage. Even better, starting at level 5 the firebolt cantrip generates TWO bolts, so the damage is really 2d10+2*cha (assuming you hit with both). This is not a negligible amount of extra damage! With 20 charisma each bolt is doing on average 10.5 damage (and you get even more bolts at higher level)
Firbolt only generates one bolt, so a 6th level dragon sorcerer would only deal 2d10+(1*)Cha. Still not insignificant, although probably not worth 2 (3 in BG3) sorcery points. Although, there is no dodge action in BG3, so every other action becomes more appealing...
Warlocks' Eldritch Blast is the only(?) cantrip that generates multiple bolts instead of dealing more damage with a single bolt, which is why the EB + Agonizing Blast combo is so powerful - you deal your Cha mod in additional damage with every blast, practically doubling your damage. So if a Warlock could gain access to Quicken, quickening EB and then casting it normally would be pretty solid.
