When you need to sell your products to multiple countries (especially in Europe), you want to have dedicated Storeviews which are fixing the complex parameters of Locales, Currency, Allowed Shipping Destination, TAX, etc.
But Magento doesn't allow to funnel the Registered customers to some dedicated storeview, specially designed for matching their core parameters. And there is not extension existing currently in order to force a customer into its own dedicated storeview, at moment of login.
The idea here is about bringing into Magento 2 roadmap, the ability to force a registered customer to a specific Storeview at the moment of Login, and allow Admin to manage this functionality.
This is also to allow Admin to fix the Allowed countries at StoreView level (vs.only at Storelevel today), in order to force the customer to select the StoreView of its country of Residence/Registration.
Such feature would be very useful for all merchants who has a market perimeter beyond one country (it would mean a lot of merchants). It would also be customer friendly and avoid Account creation errors made by the customer. If you need more details, please comment.