There is legitimate value added by robos that aren't accessible from target date funds. As to how valuable, it is up to the individuals to decide.

- tax-sensitive allocations (i.e. munis in taxable account, reit, total bond in tax advantaged account) - Continuous tax-loss harvesting - Continuously adjustable allocation - forecasting and allocation advice - "goal based" accounts

Also user experience is worth something for some people: - UI/Apps - statements, trade confirms, tax forms - electronic only (no reams of paper sent to you) - ease of transferring funds in/out

Also note that it can be cheap. WiseBanyan is presently free (charging 25bp to turn on TLH). Betterment at 15bp ends up being only 10bp more than Vanguard's Target date funds funds at 18bp.