You can install Drupal and additional modules and themes without Drush. It's just a sequence of UNIX commands, like wget
, tar xzf
, cat
. You can even write a Makefile
and use GNU make to deploy a website. But you don't want to do it (unless you have huge amounts of spare time at your diplosal). Drush provides a lot of best practices and convenience layers to bootstrap and deploy a Drupal installation.
The only reason not to use Drush is, when your server is only reachable via FTP. But then I would do drush make
or all the drush dl
on my local box and upload the resulting folder structure to the server.
Use Drush. ;)