Are you saying Angular and Bootstrap provide you the same things? I do not see in what world those two are synonymous, one is basically a glorified ui kit with some limited js backed widgets, the other is a framework for building applications.
Let me explain. I see two groups of bootstrap users:
1. Those that use the framework for JavaScript tooling. Things like dropdowns, hamburger menus, tooltips, etc. They typically don't use any of the prepackaged bootstrap styling. This was me for a long time.
2. Those that use the framework for both aesthetic specific CSS and JavaScript.
Angular helps Group 1 rid themselves of bootstrap. Group 2 is largely helpless.
The full-bootstrap-stack is perfectly fine for things like side projects.