Honestly, my instinct is to avoid learning a new program for such a particular use case, and just continue to use MailChimp, is there a value prop I should be aware of?

I could see small businesses using it if you could automate the data capture. Example, adding the capture to the point of sale at time of transaction, automatically sending a follow up email 24 hrs later, with the merchant needing to do nothing except the original setup.

SMB operators are taxed on time, adoption requires a significant overall time reduction in the value prop (imo)and convincing them of that will get trials.

I like where you're headed with it, keep it up!