TL;DR
Should you pull for Yanagi Koharu now? If you need her, yes, as her rates may not be this high again.
Who is Yanagi Koharu?
Yanagi Koharu is a character from Shoujo Kageki Revue Starlight, now featured in Waifumaster. She is a talented and passionate performer. Koharu is known for her exceptional skills and dedication to her craft. As a rare character, she is highly sought after by players.
When to pull — daily-free pulls vs paid pulls, hard-pity math
The decision to pull for Yanagi Koharu depends on your current progress and resources in Waifumaster. If you have been saving up for a specific character, now might be the time to use your paid pulls. Daily-free pulls can also be useful, but the chances of getting Koharu are lower. Hard-pity math comes into play when you have pulled a certain number of times without getting the desired character, increasing your chances with each pull.
10x vs single pull math at this rarity tier
At this rarity tier, the 10x pull math is more favorable, as it guarantees at least one 4-star or higher character. However, if you are close to the pity threshold, a single pull might be a better option to avoid wasting resources on unnecessary pulls.
What if she's a duplicate — trade vs master vs unlock
If you already have Yanagi Koharu and pull her again, you have a few options. You can choose to trade her for other characters or resources, master her to increase her skills and abilities, or unlock new content and storylines.
My recommendation
Based on the current rates and your needs, I recommend pulling for Yanagi Koharu if you need her. Her rates may not be this high again, and she is a valuable addition to any team. However, if you are low on resources or have other priorities, it might be better to wait.