A short proof of Host's equidistribution theorem

This note contains a new proof of Host's equidistribution theorem for multiplicatively independent endomorphisms of $\mathbb{R}/\mathbb{Z}$. The method is a simplified version of our upcoming work on equidistribution under toral automorphisms and is related to the argument in [HochmanShmerkin2015], but avoids the use of the scenery flow and of Marstrand's projection theorem, using instead a direct Fourier argument to establish smoothness of the limit measure.