Odd to me

[aslitumerkan]

Their wands are only useless when they are saying spells at the same 
time aren't they?
Sorry, but I don't trust the movies. Lupin doing that was just a nice 
show probably. 
However, you are right about the first times they do magic are without 
wands. But still, I don't understand why then is expelliarmus such an 
important spell, and also, why didn't Dumbledore do anything when he 
was hit by this spell?