What's the point of the will if the money will still go to the Estate.

I was advised to add my kids on the will as they are under age. Which I eventually had sorted. The lady who assisted informed me I need to call the life cover department so they can update from estate to trustees which I did I was told by the agent it can't be done and the money will go to estate as I don't have a beneficiary which I'm failing to understand the purpose of the will at this point. I am now really considering going back to FNB cause honestly better the devil you know. I'm now paying for a life cover that my beneficiaries won't even access. Hopefully this will be sorted cause I don't understand why I will sign the will which if my kids are still under age my life covers down the drain. This is emotionally exhausting and it's clear the next best step is to go back to my previous insurer.