Hi @Kristina hi there,
If you do it right, and above all, HONESTLY, then reviews are very valuable. They’re crucial for customer acquisition and retention. We actively collect reviews face-to-face in my store, directly at the checkout. Of course, only from the happier customers. 
This way, I have genuine and authentic reviews, to which I respond promptly and express my gratitude. As a result, I always get a lot of written feedback, meaning customers take the time to share their experiences. Just a few stars without any comment are very rare.
Quality over quantity.
…and thanks to the Elfsight widget, I can show it off on my website! 