Are the instant Star Rank offers per dragon worth it?

The store sometimes offers an instant Star Rank upgrade targeted at one specific dragon (1★ → 2★). Examples seen in game:

• Syrax (Legendary): +20% to all stats and unlocks the *Mindful Synergy* Habit, offered at €34.99
• Shadowsong / Daemoros (Epics): +15% to all stats and unlock a Habit (Ensnare / Instill Fear)

What you're really buying: a star jump (so stats plus an unlocked Habit slot) immediately, without farming the Relics.

Worth knowing before you buy: the per-star bonus depends on rarity (Legendary +20% > Epic +15%). Since Star Rank is permanent, the gain lasts — but the same result is reachable for free with enough Relics. So it's a time shortcut, not an exclusive effect.