Click and collect increases offline sales by driving the customer to the store. Having visited the store in person, the customer might be prompted to buy more. Even if the customer does not go through with the purchase online, they tend to visit the store on knowing the stock availability, as some prefer to examine the stock physically before the purchase.
Choice of assortment can break or make a particular brand. Consider a scenario where the product assortment is extensive. For example, if there are about 100 different varieties in a soft drink line, the customer would probably have a hard time picking a particular variety.