It makes tab completion work.

At the start of a line? So you want to run a script or executable in the current directory. PATH doesn’t contain . and ./ is necessary.

As an argument in a line? My shell offers completion from the current directory without ./ just fine.

	▲	alganet 8 hours ago \| parent [-]
		Let's say you have 100 programs in your PATH that start with the letter "g", but only one program in the current folder that starts with "g". You type `./g[TAB]` so it autocompletes automatically to the local program instead of cycling through dozens of results you know you don't want.