Q in short: I can think of ways in which remembering those who have died benefits us (e.g. reminds us that our time here is limited). And of course, the common לעילוי נשמת of doing (or causing) a mitzvah in their merit - benefits them. However, in what way does *simply stating their name זכירה benefit the deceased themselves as it seems from the Rashi below and practice of some form of memorial (attaching their name to shul, sefer, etc)?
More detail: Rashi in Megillah 3:9- explains that when Rus asked Boaz to marry her (it wasn't for the sake of yibum as Rashi holds (1:12) that she converted after Machlon died, and thus wasn't זקוק ליבום) therefore he explains her request for marriage was as a package with the acquisition of his field so that "שיזכר שם המת על נחלתו כשאבא אל השדה יאמרו זאת אשת מחלון" (so that people will remember the name of the deceased (Machlon) - when I (Rus) come to the field they'll say this is the wife of Machlon.) see ציץ אליעזר חלק יז ס' מב
Thus it seems that there is a benefit to the deceased themselves when their name is mentioned "down here" (or at least in connection with their field). My question is how/why should it benefit them? Being that this world is a "corridor" to עולם האמת, once they've gotten there, to what benefit could it be to them to have their name mentioned in עולם השקר? Especially as it seems from that Rashi that it's not even being mentioned in relation to their good deeds (כענין זכרהו לטובה) but simply the mention of their name (at least in connection to their field)