No, you don’t have to offer rewards if you don’t think it’s suitable for your business. The effectiveness of rewards, and therefore whether or not you should offer them, depends on your business and what it does.
For most investors, rewards are not a leading factor when considering whether or not to make an investment, however, they could influence an investor's decision about how much to invest.
If you do want to offer rewards, we suggest you consider how rewards could tie into the overall strategy of the business. For example, if a key objective is to drive customer acquisition or retention, you may consider offering a discount for new customers or to reward existing customers. You can read more about what rewards to offer, here.