Sorry to say , You have seen Many alt tags addressing the same one or two keywords . Not all Pages on the website . That is stuffing . free search engine submission Blind relief
Hi yes one can rank high in Y without being in the directory. Be aware that if you go for the directory it will change your title and description in the Y SERPs. This may or may not be helpful but it's irreversible for at least a year! Expat
No, I am talking about stuffing every alt tag on one page with all your targeted keywords for that page. That is alt tag stuffing.