Higher Style rarity increases base stats such as attack power. It is a reason to inspect a new core, but it does not tell you which active skill the Style will have or whether its moves suit the next enemy.
Compare the numbers that are actually displayed
When a Style Card appears, check its visible stats alongside your current option. Use the values on the card rather than assuming a fixed percentage increase for moving up one rarity tier.
The available material does not establish a universal stat multiplier for every rarity. A higher rarity label supports a stronger base-stat expectation; it does not justify inventing a complete tier chart or a damage formula.
Separate rarity from Sync Level
Reacquiring the same Style raises its Sync Level and improves its Style Bonus. Those equipped bonuses can apply even when another form is active. A rarity label and a Sync Level therefore describe different parts of the build; check both instead of attributing every stat change to rarity.
Keep skill choice in the decision
A Style's active skill is a separate part of the offer. Cores from the same type of monster can produce different skills, so a higher-rarity replacement may also change how you fight.
Before accepting it, ask whether the displayed skill helps with the encounter ahead. An ability that is hard to place against a moving target can be less useful to your immediate plan than one you can apply reliably.
Read the card before you replace the form
- Identify the offered Style and rarity.
- Compare the displayed base stats with the current card.
- Read the skill description rather than relying on the monster name.
- Accept the new Style only after considering both the numbers and the action it supplies.
The card lets you decline a Style you do not want. You do not need to trade away a useful ability solely because another card has a more attractive rarity label.