Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Why might a robo-advisor service like Betterment be preferable to just buying a single well-performing index fund like SPY?
Good for lazy investors, time-restricted investors, investors with little knowledge, investors who want a hybrid of advice and tools without paying the crazy fees of mutual funds or an advisor. The biggest advantage, is that it is easy, quick and convenient If you have the time and knowledge, this might not be for you