The Mainstream Press doesn't emphasise them if they're not significant, probably because as "nobody in this balot represents me" they represent a criticism of the very system were that Press is Mainstream and it's way harder for mainstream politicians and the politically-affiliated Press to dismiss such votes as merelly "not engaged in politics".

Blank vote counts are however formally reported and available, so at the very least you can expect that politicians whose win/lose can be decided by a few percent more or less votes would pay attention to it and be interest in swaying at least some of those pople casting blank votes since they are clearly engaged enough to vote, though voting "none of the above".

Around here in my experience they were a fraction of total votes (maybe 1%), but then again I'm in a country were there are around 10 parties with Parliamentary representation, even though the voting system is still a mathematically rigged electoral circles one (though nowhere as bad as the US) so people are far more likelly to find a party that appeals to them and is actually electable.