I hope the data in the screenshot answers this question well enough. This is just the 7th day of the campaign, and the conversion rate is more than 19%.
Hear me correctly: I do not mean to say that reviews are not important. Quite the opposite, I am sure reviews are essential for success. But do not let the absence of reviews (yet) stop you from actively promoting your book.
Have you had experience with good book sales without reviews, or with a minimal number of them?