Never used any icon on carplay home screen, carplay is only usefull for navigation and listening music. For this you need exactly two icons...
(The 3rd usage would be phone calling, but that only works on phones with english locale. There is no siri support for my language, and it is impossible to search the phone book in carplay: each time you type a letter in the search bar carplay jumps to a different letter. I think this is true for any latin type alphabet with more than 25 letters. This bug is present from the first version of carplay, and seems apple cannot fix it.)
(The 3rd usage would be phone calling, but that only works on phones with english locale. There is no siri support for my language, and it is impossible to search the phone book in carplay: each time you type a letter in the search bar carplay jumps to a different letter. I think this is true for any latin type alphabet with more than 25 letters. This bug is present from the first version of carplay, and seems apple cannot fix it.)