"Brands are seeing that this branded content ad product sometimes helps overcome challenges they have with organic branded content. They are exploring ways that brands can amplify branded content."
Ashley Yuki, Instagram product management lead.
Whereas brands can now pay an influencer for promoted posts that only their followers would see, "branded content ads" allow the brand to promote them more widely just like any other ad on the platform.

In 2017, Instagram released its first branded content tools as part of its response to popular accounts promoting products without disclosing the relationship to advertisers, which has been a regulatory problem that has vexed digital platforms. Instagram has a way for these creators to tag the brands and disclose when a post is sponsored. However, if a brand wanted to take that post from the creator and put ad dollars behind it to reach more people, it could not do so within the branded content partnership program.
The nascent influencer marketing industry on social media has been dogged by usage of bots and fake engagement tactics, while the recent Fyre Festival scandal highlighted transparency and accountability problems. The ad industry is now demanding more vigilance on the part of the platforms to purge phony activity and provide accurate measurements. If so-called influencers have fake followers and stats, then a brand can't have confidence collaborating with them.