Whats good about having a surf board with non removable fins?

A surfboard with the fins glassed directly into the board will be lighter in weight then a surfboard with with removable fins. The boxes that the removable fins fit into add weight. Most people prefer a lighter surfboard.

if its just to start surfing i wouldn't worry about what kinda fins id more worry about having a wide decent lengthed board cause you want a reasonably stable board to start on. But glass in fins are stronger but when they do snap its way more hastle where as if they had fcs it usually doesn't crack the fibreglass