Apart from rarely being useful, they don't really provide the right kind of feeling for your success. They can, at most, provide which shade of success you are facing. There are many kind of readers and reviews just tell you what kind of readers are on your novel. Nothing more.
Taking in only good stuff and pumping yourself up to unspeakable levels might be toxic on the long term and might hamper your growth. But, especially when starting out, very few writers have the fiber to take the amount of shit that internet will throw at them. People on the web are not held accountable for what they say, meaning that they will spout the meanest things about your content. And the thing is that [I believe that written critics are not a reliable metrics of success. And you should Ignore vanity metrics and focus on what really matters. In fact, I firmly believe that Ratings are Vanity Metrics