I agree that Akita is nonsense. I think the Dimond Brothers gave the best reason for the rationale behind these, assuming they're real (i.e. of diabolical agency) and not derivative of psychological issues or fraud on the part of the "seer". As Padre Pio told Father Amorth, and as others who read the Third Secret have indicated, it's about a spiritual chastisement, the apostasy, the anti-Church, and not about physical chastisements (Padre Pio explicitly said this to Father Amorth).
But the emphasis of Garabandal and Akita is on some kind of physical calamities, with Akita's "fire from heaven". This is a distraction from the actual message, which indicates that the chastisement is well under way, since about 1960. So while everyone is looking up to the skies, they're not seeing what's right under their noses. Garabandal (clearly diabolical) came right after the Third Secret was to be revealed, Akita a little later, after the NOM was released. Akita also speaks about "bishops vs. bishops", as if to characterize the strife as something internal within the Church rather than that nearly all the bishops would become apostates.