Impressive collection of high quality surfaces !
The https://materials.3dcoat.com/scans page tends to block the scrolling function so you only can see a few materials at start.
This seems related to the size of the browser window (4k display here) and goes away when resizing to Full HD or less.
Please adjust the responsive design of the page.
Credit card as the only payment method is a restriction that will limit the success of the library and the subscription as only model is a no go for lots of people.
A purchase of packages (points /credits to spend on materials) and PayPal would be a welcome option.
The presentation of the marterials is well done.
I will check the quality of the materials with the free download available.
Thanks for this great reveal !