In areas with such slow/non-existent Internet connections, the computers are often too old to support booting from USB. This is still a good step though, as the computers can get modernized in certain spots, such as a single cyber cafe or school, and then Linux can be installed regardless of the speed or availability of an internet connection. In this regard Africa resembles the USA in the mid 1990's, when the internet was at modem speeds and we installed Linux from floppies (Slackware) or later, CDs.