@hellomichellewong how's it going? Ok, I hear you.
You offer a discount. You say optin rate is high but compared to what benchmark? Can you share a figure?
You also say conversion rates for the checkout is low. What are your targets? What's your industry average? Low compared to what? The millionaire lifestyle?
Often offering a discount at the same time as a purchase unintentionally puts customers off 1. because they have to do two things at once. And 2. they have to enter a code somewhere else (often they can find where)
That means there is a 50/50% chance they will check out. (Owch)
Discounts are distractions.
How can you add value and make it a super high touch experience?
Often new e-commerce owners want to offer discounts to get customers, why do that? Why put yourself head to head with Amazon et al. You will lose.
How about offer premium service, with fabulous extras with your personal signature?
Rise above the discount brigade with grace and style. You want great customers for life, not cheap customers who are attracted by a 15% discount offer, and will expect discounts from here on in.
Let me know how it goes.