When might one be obligated to recite a Berachah Acharonah after eating fruit, despite that he ate less than a k'Zayis?

Is the entire reason that we ask to return to the Land of Israel and to Jerusalem, merely for its physical bounty, "to eat of its fruits and be satiated from its goodness"?! The Gemara (Sotah 14a) makes it clear that when Moshe begged to be allowed entry to the Land, this was certainly not his motivation!

We would expect this "Berachah Achas me'Ein Shalosh" to contain only those themes mentioned in Birkas ha'Mazon. And yet it adds many new elements, such as the Mizbe'ach, ascending to Yerushalayim to eat of its fruits, and blessing Hashem in purity?