Some are both multinational and cover several sectors, for example Yamaha.
Here are just a few Yamaha twitter accounts: @YamahaMusicEU, @YamahaMusicUSA, @YamahaUK, @YamahaAV, @YamahaMotorEU, @YamahaMotorUSA, @YamahaMotoGP.
When a company makes a product they may or may not wish to make the same announcement on the accounts for that vertical across different regions. Most often the really big ones will probably make different announcements due to both differences in desired wording and in launch dates, but still the point stands that they might sometimes wish to post the same news.
Almost all top tech companies have multiple @accounts, even Twitter does! I've seen multiple times how these companies post same announcements on multiple accounts. Even Twitter sometimes does that, for example when announcing something important in relation to security or policy, they post the same thing on the dedicated channel and their main channel.
Moreover, there are tons of tools build around Twitter API, like consumer ones: buffer, hootsuite and several other big enterprise tools that enable exactly that - connecting multiple accounts and cross-posting/scheduling the same tweet across all channels (as usually these tools also connect to facebook, linkedin and g+).
So, I still don't understand Twitter's move here, they are effectively declaring most of their business use cases to be outside of the guidelines. I'm surprised.
First of all, big companies don't usually have multiple Twitter accounts; rather, all their representatives communicate from a single account.
Second of all, even if a company did want to use a multitude of Twitter accounts for some reason, the ban is on posting the same content to multiple accounts, aka spam. Not simply having multiple accounts available to choose from in the same interface.