It's for grinding in spots that would be hard to reach with a traditional angle grinder 

https://www.acmetools.com/dewalt-5-in-125-mm-20v-max-xr-flathead-paddle-switch-small-angle-grinder-with-kickback-brake-bare-tool-dcg413fb/885911540216.html?gad_source=1&gclid=Cj0KCQjwvpy5BhDTARIsAHSilymCA_mnImwZllzOzX8IkfKGu5eI0RECWfVmFotGTVKKqzpaMOAdHNgaAs_-EALw_wcB