Hi @brambil,
Thank you for your message, I appreciate the feedback and suggestion for improvement. If I can think of a way to improve this native WC email restriction behavior in a future release, I will certainly try. This plugin applies coupons automatically, but as of today all email restriction logic is native to WooCommerce. Usage Restriction and Usage Limits tabs are WC features and this plugin does not introduce or manipulate the logic in any way.
This thread describes a common scenario with email restriction in WC. In short, WC will allow a coupon with email restrictions to be applied until the customer email is provided. Once the customer email is provided at checkout, WC checks the email against the coupon email restrictions and will only remove the coupon at that time… https://projectdmc.org/support/topic/email-usage-restriction-not-working