Establishes the upper-bound of her on-page Devil-Fruit demonstrated power: 10,000 kg (~22,000 lb). The attack-name is her only named technique across all her appearances — Oda does not grant her any further named attacks, suggesting the 10,000 Kilo-Press is the upper limit of her combat-vocabulary.
The attack also locks in the Officer-Agent fruit-doctrine-articulation-then-deployment grammar: like Mr. 5’s I’m human dynamite monologue + Nez-Palm Cannon deployment (Ch. 0111 p.12), Miss Valentine articulates the doctrine (“I have the power to change my weight at will…”) and then deploys it (“…10,000 Kilo-Press!!!”) in the same panel-sequence. The pattern is the canonical Baroque-Works Officer-Agent fruit-doctrine reveal template.