Landscape Weight Questions

I was watching UE4 Stream for Landscapes, Andrew said to use Non-weighted blend then assigning Layer Infos for each layer, any tutorials I watch or read tells me to use Weighted Blend instead of Non-Weighted then using the same workflow. Can someone explain each one? Also, what is the difference between Wrap and Clamp type of Texture sampling?

If you paint a Weight-Blended layer, all other weight-blended layers will be erased as you paint. Sum of all weight blended layer weights in any given point is always 1.
Non-weight blended layers are independent from each other.

Wrap means that the texture will repeat itself after exceeding 0-1 UV range. Clamp means that It won’t,