Feedback on MVP: Marketing calendar API for developers

Hi, my favorite community,
I am finally launching Campaign Days (https://campaigndays.com) after working on it for 4 weeks.
The motivation behind this service is to help developers who run marketing campaigns. They can just hook their marketing platforms with our API and forget about setting dates for their campaigns. MVP version is launched with 3 calendar types:

1. Public Holiday Calendar
2. Long Weekend Calendar
3. E-Commerce Calendar
   Check out https://campaigndays.com and let me know what do you think about it. A couple of points I have been thinking about:
4. Is it a valuable service for which people like to pay?
5. Are there ways to improve the offerings?
6. Can I build more features on the same theme?
   Really looking forward to your feedback.