But on turn three, the Spectral Hand starts to kick in with Bestow Curse, Contagion, and Vampiric Touch, all at range. It can also be used to deliver beneficial spells to the tank without putting yourself at risk (various protection spells [good, evil, arrows, etc.], Spider Climb, Stoneskin, etc.). That is why it is worth a two round casting time. Spectral Hand lasts for caster level # of minutes; and it could be cast before the room is entered and voila, round one Combust on a spellcaster. And if the room is empty; with a little hurrying, it will last for the next room, too.
Add the Extend Spell feat for a one level cost and Spectral Hand lasts for a minimum of 100 rounds (10 minutes), 12 minutes for sorcerers.
Or you could Scorching Ray on round one and round two...
Players in my game liked Spectral Hand so much that they developed a higher level version that worked with higher level spells and included a self-destruct mechanism to blow it up in the enemy's face for a little extra bang when the touch spells ran out//And another higher level version that included its own touch attack for minor damage (like a claw attack) for the same situation.
Fireball, Lightning Bolt, Magic Missile, and Scorching Ray are good spells, but some players like to try out different things rather than just burn up the enemy's hp: set them on fire, give them a disease, steal their hp to heal yourself, suck away their ability points, give them a penalty to most rolls, 50/50 do no action, etc.
Without Spectral Hand, touch spells are only really good for a tank (who usually has something better to do than cast a spell). Clerics, with their armor and bigger Hit Dice, can use touch spells in melee, but most that I have seen don't.
Ciao,
Dave