FYI, GDD girls are named after real erogame maker.
Alice - Alicesoft
Yuzu - Yuzusoft
Seiba twins (Momoi and Midori) - Cyberworks (Wendybell and Tinkerbell)
He's already standing out by lending huge ship to them (except if huge magic ship does exist in that world). Add one more mysterious power won't hurt.
But story wise, it just for show casing different type of ship before the ultimate goal (luxury liner)