It seems to solve a very similar problem to Angular UI's bootstrap project: http://angular-ui.github.com/bootstrap/
The popovers allowing external templates and custom scopes is one example, and the inclusion of navbars, date and time pickers instead of pagination, accordions and carousels is another.
If it works, I'd say I like it more than Angular UI's version, which is probably simpler to get up and running but something that you'd run into the limits of more quickly.
All three of them (angular-ui, ui.bootstrap, angular-strap) have been a pleasure to work with.
The main difference between the two seems to be how they handle templates. UI Bootstrap has a set of default templates that can be overwritten, whereas AngularStrap doesn't. AngularStrap also includes date/time picker directives.