get_template_part() is useful for organizing chunks of your site into reusable parts. If you have parts of a larger template that might be used in multiple templates, it’s useful to use get_template_part() to pull these in rather than have the same markup in each separate template.
The real power of get_template_part() is that it allows child themes to override these only these template parts.
For example, you mention a swiper slider. Using get_template_part(), someone could create a child theme and override the swiper slider template part to be a grid of images instead of a slider. All they would have to do is create a template file that’s named correctly in the child theme and WordPress would use this new template part instead of the parent theme’s template part.