Think about what happens when you send work for review. You email a link. Your client clicks it. They get a sign-up form.
Some of them make the account. Some reply to the email with their notes instead, and now the feedback lives in your inbox rather than on the frame. Some forward it to the person who actually has opinions, who now needs their own account. Some do nothing for four days.
None of that is your client being difficult. It is a wall you put in front of them, on your behalf, because the tool charges by the seat and a free anonymous reviewer does not fit that model.
In oketto a share link is the credential. Open it, type your name once so comments have an author, and you are commenting. There is no account, no password, no seat, and no cost. Reviewers are unlimited because a reviewer is not a billable unit, they are the point of the product.
The tradeoff we accept: anyone holding the link can comment. That is the right default for client work, where the link goes to people you chose. Links can be revoked when a project ends.