Why would I need contingency when I have celerity?

[ahenobarbi]

I got my character access to contingency and started wondering what condition and spell should I use. After reading a bit on the subject I think there is no point in setting contingency to activate when I could use immediate action - I can just cast celerity.

So why would I use Contingency? I can see two possible uses:
1. Rescue me when I can not act.
2. Action abuse (cast a spell, have Contingency cast a second)

1. is hard to setup - only contingency that would universally work is teleporting back to allies. And I don't have ideas for 2. (because the spell must work on me. And I have all buffs I want active).

So why would I want contingency?

[Snowbluff]

Celerity dazes you, which is pretty awful.

[Lostbutseeking]

Enemy wizard casts JustDieNow.

You cast Celerity - Teleport.

Enemy Wizard casts Celerity - Counterspell.

You then die.

[Urpriest]

You can't use Immediate Actions when you're Flat-Footed, so you can't use Celerity until your turn. If someone attacks you before your turn in the encounter, for example if they have a surprise round, Celerity won't protect you/

[Rubik]

Why would you need Contingency when you have Celerity? For Contingency+Celerity, of course. After all, you only have one immediate action per round, and you can't use that outside of battle or when you're flat-footed.