Question about CWT #773

In CWT code, the wavelet is first integrated:
int_psi, x = integrate_wavelet(wavelet, precision=precision)

then convolved:
conv[n, :] = np.convolve(data[n], int_psi_scale)

and then finite difference of convolution is taken:
coef = - np.sqrt(scale) * np.diff(conv, axis=-1)

which is equivalent to not integrating the wavelet in the first place.

Why is it done in such a way?