Blender makes meshes.
Houdini can interact directly with the landscape system, making it easy to produce world composition levels - in theory anyway.
So…
learning blender is definitely a good idea anyway, but it’s not really directly related to what you asked for.
Again, if you need to use the grass node for distributing procedural meshes you must use the landscape.
(And we all wish they’d just allow the node to work on anything)…