Spline point tangent question


I’ve been messing around with Spline Mesh Components and wasn’t really sure about tangents. I know they are used to make curves and such but I noticed something strange when testing some blueprint made splines.
With the tangent on the endpoint of the spline set to 0, the spline stops at about 90% of the way. It doesn’t reach the endpoint I put in. Why is that?
Some basic information about splines and tangents are also greatly appreciated!