It may be worth catching a Geodude here as it will be helpful against the third gym that focus on Electric-type. Besides being immune to Electric-type attacks, Normal-attacks will only do half of the damage due to it being a Rock-type Pokémon. Although slow, its defense can withstand most of the physical attacks.
Being a Poison and Flying-type, Zubat is an advantage against the Grass-type Celadon Gym later on. Upon evolution, not many Pokémon are match-able to Crobat‘s speed. It can earn a place in your party if you like a Pokémon that mostly strike first in battle.