When you make a great content, interact with followers and inspire them, you become their authority. They believe you. So you should recommend proven products. Once you make an advertising for the product, you take responsibility. Unfortunately, many influencers forget about this.
To become an influencer, you should earn trust and build long-term relationships with your followers. Promoting defective things, you risk losing the trust of the audience and brands that don't want to cooperate with unscrupulous influencers.