Statistics of material lines passively advected in stationary homogeneous isotropic turbulence of an incompressible fluid are investigated from the viewpoint that material line stretching is a multiplicative process. It is shown by a simple argument based upon this perspective that material line elements cannot be treated equivalently in the line statistics. In other words, a frequently used assumption (G.~K.~Batchelor 1952) of their equivalence is not valid in general. The invalidness of this assumption is further confirmed by estimating numerically the correct stretching rate of material lines as 0.17/(Kolmogorov time), which would be 0.13/(Kolmogorov time) if the Batchelor assumption were valid. This substantial difference is a manifestation that turbulence has spatial inhomogeneity of order of the Kolmogorov length and none-zero finite correlation time of order of the Kolmogorov time, reflecting the existence of small-scale coherent structures.