Why are all the fields in Prefill checkout data, and the custom price is required?

[Akshithpottigari]

While creating a checkout, when I pass variant and store ids why the custom price is required, and I only want to prefill the email field, and other fields like the customer name and billing address are filled by the customer.

let link = await LEMONSQUEEZY_CLIENT.createCheckout({ variant: process.env.VARIANT_ID as string, store: process.env.STORE_ID as string, custom_price: 15000, checkout_data: { email: user.email, }, });