It is not as important for handmade and OOAK items. It is very useful for items that are new and have UPC numbers. If you do a search and then click shopping you will get results that have a compare prices box on the right side, and this is extremely useful to find price comparisons, and locations of items. The way your item gets put into these compare boxes is by supplying the UPC, MPN, and manufacture of the item in your feed to google. All the sellers who have the same UPC get put into the compare prices box. Since most companies did not start using UPC numbers for there items until the earliest was 1993 you will not really see any Etsy items in the compare boxes as 1993 would not qualify as vintage yet.
The shopping search engine is very useful for research. do a search for a like item you are selling, and then click the shopping tab, and this is a great way to see how other sellers across the web are writing Titles, descriptions, pictures everything you are basically doing. You will find better ways to list your items by doing a few minutes of this everyday.