Maybe an example of what invoicing is like and what integrations it has would help. Maybe an example of what insights it will have over my time management.
You should state on the site that it's a beta/work in progress so people don't think it's a finished product and leave because you don't offer a feature they want yet.
As for the design, I would encourage you to sign up, I am sure you will be very surprised with what you'll find. The app is VERY polished (for a beta).
We are spending a lot more time on the app than we are on the website. That will change soon, but this is why you are perhaps finding the website's content to be insufficient yet.