the only issue with encrypting the data before you send it up to the cloud is where you store your encryption keys.
if you loose those keys you loose your data, so it does no good to store your data in multiple places if your keys only exist on one machine.
for many people who do not have good ways to store the keys, they are actually better of in many ways with the data in the clear so that they can pull it back down to a replacement machine if something happens to the first one.
yes, this is not good from a security point of view, but in this case the security risks need to be balanced against the availability risks. which one is more important will vary from person to person.