Anyone knows how to use Basis Curve LOP?

Got this working by defining a vector array call points with position coordinates and also a curveVertexCounts integer array with the number of vertices to define the curve. If you plan to render the curve you’ll probably need a float array attribute call widths which will need to be same array length as points array.

The Basis Curve LOP is really not a great way to author curve primitives (as you've seen - though it is possible with a Wrangle LOP). It's much easier to use SOPs to generate your curves, and then use a SOP Import.

The Basis Curve LOP is a very low level utility node for making block edits to a bunch of USD curve prims (turn off subdivision on all the curves in the whole scene). Or to create an empty placeholder prim so that you have a primitive of the right type at the expected location in your scene graph, with the intention of filling in the real data later (create /world/characters/bob/hair as a basis curves prim, but don't populate it with any actual hair curves - that data will come from that CharFX department later in the pipeline).