Building on these gives the developer a perpetual abeyance on any capital gains, they don't have to pay tax on their profit at all! These QOZs were intended to incentivize the development of land in rural areas where development is not being done by the capital class, but are being abused to put money in the pockets of the rich to ensure there's somewhere to keep the slave class close by all the tech bros so they can cook their lunch.
Heaven forbid they were actually used in rural areas and created jobs where these humans could leave the city and seek some semblance of self-determination.