Isn't MTNs website running on Sharepoint ? That might explain a few design choices. They probably created a global sharepoint template and since then been fiddling with Sharepoint apps . I won't be surprised if the skills and expertise to maintain and redesign the site to be more functional is just not there as opposed to using more of the other standard web technologies which are less reliant on Sharepoint as a base platform.
Even where i work, we have Sharepoint as intranet, but i was never comfortable with pointing this outwards to the internet and using it as a "consumer" or "retail" platform (as opposed to using it as a document management platform) . I'm sure it's capable, but all the tools and components out there to rapidly develop specific types of client facing websites is most likely not found under Sharepoint tools.
Plus, chances are MTN is still on Sharepoint 2007 (or older), when Sharepoint 2013 is already available.