Suggestion: Thumbnails' type

Right now get_the_post_thumbnail($id) function is used without any options to output thumbnails on a page.

WordPress has an opportunity to change thumbnails type, for example:
get_the_post_thumbnail($id, 'medium')
or even
get_the_post_thumbnail($id, 'my-registered-type').

Using such smaller thumbnails helps to safe a lot of traffic. And page loads much faster in compare with standard post thumbnail.

So my suggestion:
WP has opportunity to get all registered image types like that:
global $_wp_additional_image_sizes;

With help of that we can show thumb types in the select box in the widget settings, and then output thumbs like this:
get_the_post_thumbnail($id, $thumb-type) // if thumb type was selected
and in other case:
get_the_post_thumbnail($id) // thumb type was not selected

What do you think? Does it make sense?

https://ww.wp.xz.cn/plugins/dd-lastviewed/