Target date index funds - investment strategy

@Jeremy - I found your article " Seven reasons to put 100% of your portfolio in a target date index fund" to be very informative. I currently have a 401k, traditional IRA and personal fidelity account all invested in the same target date index fund based on my expected retirement date. I know that the target date index funds offer great diversification, but wanted to get your thoughts on whether having all my different investments in the same target date index fund is a good idea?

Youre sticking to the same allocation across your portfolio and rebalancing would all occur at the same time.

Simplicity. I don’t see why it wouldn’t be a good idea.