Here are a few reasons:
Faster access to higher level spells
More versatility (at a minimum, when gaining a new spell level, a wizard will know two spells of that level, rather than a sorceror's single spell. the wizard can also supplement their spells known by purchasing and learning new spells)
More forgiving of mistakes in spell selection (a wizard can learn new spells and just not memorize a spell they thought was good but later realize is weak, but a Sorceror is stuck with that useless spell taking up a spells known slot for several levels)
Bonus metamagic and/or item creation feats
Metamagic spells don't have a longer casting time
More skill points (because your casting stat is Int)
Better skill list (the sorceror has bluff, but only has Knowledge (Arcana) compared to the Wizard's access to all knowledges, also the Wizard's primary casting stat synergizes with their knowledge and spellcraft skills, while the sorceror's casting stat adds to only one of their skills)