If you've already got a 401k or IRA for retirement, you should definitely keep funding these! Raise Investment accounts do not benefit from tax-advantaged status like a retirement account, but they have a few unique advantages to retirement accounts:
Only Raise Investment provides you with the initial, large investment to jumpstart compound interest. In a retirement account, as well as in other traditional investing accounts, the you compound from whatever capital you invest. That's not the case with Raise Investment.
Unlike a retirement account, you can cancel your Raise Investment account whenever you want and begin using these funds before you turn 59 1/2. With retirement accounts, you'll incur a penalty if you begin taking disbursements before then.
Raise Investment is a great compliment to a retirement account, but it isn't intended to outright replace them, or compete with them.