Tech sites try to create controversy whenever possible to increase ire-related engagement and gin up impressions. The author goes on and on without apparently undertaking the research to find out why Arc needs an account, which is easily found on the company’s site.
In short, an account is necessary so Arc can sync data between devices and support the collaborative aspect of Easels. It also facilitates communication with users—I’ve now heard from people who have had responses from what sounds like a small support staff.
I can’t get exercised about the need for an account. I have nearly a thousand accounts in 1Password and haven’t experienced any negative side effects because of it.