Hey Gary, no problem.
The reason you weren't able to sign up yet when you went to the website is that, as a research participant, Miro employees will have to run you through the prescreening and screening process (including informed consent). Then, when ready to participate, you will be invited to the platform where you can access the study and the associated app.
As for your second question, the idea behind the company is to create a tool that is more sensitive than traditional neurocognitive tests and ultimately better suited to the earlier diagnosis of neurodegenerative disorders. The purpose of these studies is to validate the tools alongside traditional paper-and-pencil neurocognitive tests and submit this data to the FDA so that Miro can become officially approved as a medical device. Miro is a for-profit company, so in the Terms of Service specify that they are the sole owners of the data, but their intent isn't to sell data to anyone to make money. Ultimately the idea is that patients will be able to bill insurance companies for the use of Miro; again, it wouldn't be necessary or prudent for Miro to sell patients' data when other avenues exist.
Hope this helps!