I was looking at making my first wizard for a homebrew that a friend of mine is running and I will most likely be using summon monster quite a bit. I was wondering though, does it stay worth it to prepare the lower tier versions of this spell like I, II, and III once I have access to higher ones like VII? It just seems like the the monsters on the lower versions of the spells lose any viability in combat once you are a couple tiers past them.
I know Lantern Archons are amazing at most levels, even if the damage they deal might seem low at higher levels.
Aid can be a great buffer for your HP.
Their light rays ignore DR and aren't magical in nature, so the ignore SR and even antimagic fields. As a ranged touch attack.
Even the weakest monster can prevent a charge, provide a flanking bonus, or prevent an opponent from moving next to a squishy PC. And even if they can be dispatched in a single attack, that is an attack that wasn't aimed against a PC.