In addition to the comments above:
When using a remote node, you are using it's daemon and downloaded blockchain. If you cannot connect to a remote node, you can run the local daemon. This then needs to download the blockchain to your local machine. Depending on how fast your connection is and whether your disk is a spinning HD or SSD, this can take from hours to a week.
It's also worth noting that when using a remote node that is not your own remote node, you are trusting the remote node operator and thus can lose some security and privacy.
A common and very useful reason to run your own remote node is when you have multiple devices that you wish to use Monero with and don't want to trust someone elses remote node. For example, run a simple cloud server as your own full remote node, secure access to the daemon using something like stunnel, SSH tunnel or proxied Apache/Nginx using SSL. Then you can use your own remote node from other devices like your phone / laptop etc without having the overhead of the ~70GB blockchain on each device.