FRP rebars has great advantages but considering its structural lack of bendability and its brittleness is it structurally practical to use it?

The problem of FRP is the britile failure (there is no instructions) (sudden tension failure ) , so the factor of safety of tension failure should be higher than for steel reinforcement. That point make FRP difficult to use is seismic area.

 

FRP will not corode in field conditions, it's low weight, strong in tension and method of construction is same as steel, But it has low moduli of elasticity, tensile force stretches the matrix more than the fibers, tensile force near the end of the fiber exceed the tolerance of the matrix, separating the fibers from the matrix, tensile force can also exceed the tolerances of the fibers themselves to fracture leading to material failure. Conclusion: FRP is an engineered material that shows great promise in the future of Civil Engineering.

That will depend on the structural designer. All materials we use have its own strengths and weakness. When we design usinh a specific material, we define its properties and calculate. We then adjust the quantity required depending on the material's property to satisfy the design requirement.