Thinking about the design aspect, even though it's pretty simple and the design is the same since the website was launched more than a decade ago, the website is much superior to many modern crypto platforms which take a long time to load in our devices and don't offer the benefits to users you mentioned like freebitco.in does. I think it's a smart idea to keep the design simple and clean, because besides being nostalgic, it's also accessible to a wider audience, especially the micro earners who don't have access to brand new devices, as they are expensive to be acquired.
There is no need to change something that is already working perfectly well. If freebitcoin really wanted to and thought it was worthwhile, its team would have changed the current site design to a more modern one years ago. By the way, what kind of audience do you mean by "micro earners"? Are those users who still use the freebitcoin site as a faucet? If so, I think such users are no longer or almost not left.