Tax-loss harvesting is most beneficial for those in higher tax brackets. Tax-loss harvesting is very difficult to do manually as an individual investor since you would have to constantly monitor your portfolio for losses, then reinvest your money in a new selection in a new security that isn't 'substantially similar'.
Plenty's leverages technology to provide a sophisticated proprietary algorithm to do this for your automatically. Tax-loss harvesting doesn't benefit individuals who may not have taxes payable. Plenty is not a tax advisor; we recommend you consult a tax advisor for advice on your individual tax situation.