为什么Angular UI Bootstrap使用提供程序来处理模态和工具提示中的逻辑而不是其他组件中的逻辑？

I've noticed that Angular UI Bootstrap uses a Provider to handle all the logic of the Modal and Tooltip component, but all the other components the logic is set inside a single controller that is shared by the directive and it's sub-directives.I've noticed that Angular UI Bootstrap uses a P