I definitely like the option for reviews to be open, but there are certainly pros and cons to having only open reviews.
As a reviewer, you are expected to work for free. If reviews are blind, the reviewer doesnt need to spend huge amounts of unpaid labor to review to the best of their ability, because the accuracy of the content ultimately is dependent on the authors of the paper. If your name is associated as a reviewer, though, there is likely more pressure to perform a good review (for free), lest an error slip through that you get blamed for. There are a lot of things that you are also just not necessarily equipped to double check as a reviewer, like if an author fabricated something. It's not like you can retrospectively audit their whole process. This will likely cut down on the number of people willing to perform reviews.
Additionally, many fields are pretty niche communities where everyone knows everyone, and there can be professional ramifications to giving someone a bad review, like harmed collaborations, or tit-for-tat bad reviews back on your work.