We don't believe that spreadsheets of data about your own Twitter account are a useful way to "develop an additional product or service" and that's not how we're pitching the feature. This feature is based on requests from several professional social media managers among our beta users, who wanted a way of exporting the data to give their management reports on their Twitter usage. If we find out that anyone is paying to download our spreadsheets for the purpose of re-importing the spreadsheets to build their own Twitter-related product or service, we will take appropriate action.
Thanks for the note of caution, though. There are risks to developing a service on top of a third-party platform, and we strive to maintain a good relationship with Twitter to mitigate those risks.