A Rollover IRA is a more flexible retirement account than an employer-sponsored account. It can provide you with the broadest range of investment choices and usually has fewer restrictions than an employer-sponsored plan.
As the IRA account owner, you make the decisions about your account, including investment direction, and asset allocation; not your employer. A common goal of planning for a lump-sum distribution at retirement is trying to prevent unnecessary tax withholding. Lump-sum distributions are immediately taxable as ordinary income unless you rollover the distributions into another tax-qualified plan within 60 days. So you can use Rollover IRAs to consolidate multiple retirement assets you may have in order to relieve some tax burden.