Your brand needs to have a unique value proposition because without it, your brand can lack focus and leave the market confused as to who and what your brand is about. Confusion leads to reduced trust, and when people don't trust your brand, you lose sales/opportunities.
However, brands aren't built on a single value proposition alone. The more value your brand brings to the market and its customers, the stronger your brand can be (as long as those values support the overall brand promise and unique value proposition).
Your brand values are what will cause your target customer to consider and use your brand’s products or services rather than another company.
While brand values are perceived by you, most importantly, they are perceived and experienced in the market. If potential customers do not experience your values in some sense, those values do not exist and you leave yourself vulnerable.
Remember, a brand is no longer what we tell the consumer it is — it is what consumers tell each other it is.”
Spend time developing your brand values. Talk to your stakeholders, your customers, prospects, industry experts, etc. After all, it is brand values which are at the heart of successful branding.