Blank measures can give the impression that something is missing, for example that the composer forgot to write out a certain passage for one instrument. If you consistently never write rests in empty bars it isn't a huge problem because you'll quickly see the principle when you read the score, but I still think it's much less ambiguous if you write them all out.
There are of course some composers, like Lutoslawski, who didn't only leave empty measures blank, but even removed the staff lines whenever that instrument shouldn't play. (The following was the first thing that showed up on a google image search for Lutoslawski.)
Of course this form of notation also has to do with Lutoslawski's aleatoric techniques, but it would work as well in different music (and Lutoslawski also used it in pieces that were pretty much without aleatoric elements.) This form of notation has the advantage of making it very quick to see which instruments are playing and when they set in, which is especially important if it's a form of music that strongly relies on cues from the conductor (which a great part of Lutoslawski's music does).