Some colors appeal to buyers. Some don't. If you're going to paint to prepare your home for selling, it makes sense to paint the walls the colors that will appeal instantly to buyers. Soft, neutral colors are the 'go-to' colors. If you need to paint, choose colors that 90% of the buyers will love. There is no point painting strong colors which will only appeal to 10% of the buyers.
The aim of preparing your home for sale is to make it 'move-in' ready, so that the buyers can just roll in their suitcase, unpack and enjoy their new home. This is what will get you the highest price for your home.
Sometimes its valuable to see what something looked like before, and then what it looks like afterward. Here are some examples!