In this day and age, business almost live and breath by the reviews that they receive. Especially online businesses and small or local business. Google Listings and Google reviews are one of the most popular ways for the every day person to understand a business and if it is someone that they would like to work with.
Amazon is the best use case to look at. And it's really pretty simple.
The products that don't have many reviews, won't be seen as much. And of course bad or negative reviews is another killer in general. But if you're looking at two similar products, and one has 500 reviews and the other has 5 reviews...which one are you buying?
Probably the one with the most reviews, because you know it's been purchased more and more people like it. Again...pretty simple.
But same goes for local business like grandfather clock repair Raleigh NC. Small companies that are offering services as their means to make money. And without customer reviews it's more difficult to grow, and in some cases, stay in business.
Which is why if you're a small business owner, it's very important to have an email system to follow up with your customers after a purchase to ask for a review. Don't be afraid of asking for it, your business and products could depend on it!