Why would you ever use a Spear when Longspear exists?

[Super Cosmic Space Magnet]

They have the same damage, same crit range and multiplier. They are both Simple weapons, and both require two hands at all times. The Longspear has longer range though.

Is there ever a reason to use a regular spear..?

[mk11]

In table top you can't use a reach weapon against adjacent foes but I think that is not implemented in the game. So other things (background, feats, weapon bonuses) being equal no.

Edit: One case you might is if you are mounted. Seems that sometimes when using a reach weapon while mounted your mount doesn't attack.

[Schlumpsha]

Spears and short spears can be useful if you mount smaller animals as a shorty. Reach would actually get in the way of the pet's attack.

[Super Cosmic Space Magnet]

Huh. Interesting - thanks!